1,721,428 research outputs found
Pendolo ripiegato a bassa frequenza con elevato fattore di qualità meccanico, e sensore sismico utilizzante tale pendolo ripiegato (LOW FREQUENCY FOLDED PENDULUM WITH HIGH MECHANICAL QUALITY FACTOR, AND SEISMIC SENSOR UTILIZING SUCH A FOLDED PENDULUM)
No full textThe invention concerns a folded pendulum, comprising: - a support (F); - a test mass (PM); - a simple pendulum (SP); - an inverted pendulum (IP); the simple pendulum and the inverted pendulum being connected at one of their ends to the test mass (PM) and at the other end to the support (F) by means of 4 corresponding joint systems (G), the test mass being not connected to the support (F) and being therefore free to oscillate, each joint system (G) relevant to the simple pendulum (PS) comprising one or more joints in tension, the folded pendulum being characterised in that: each of the joint systems (G) relevant to the inverted pendulum (IP) comprises one or more joints in compression. The invention further concern a seismic sensor utilizing the folded pendulum according to the invention
Metodo delle transizioni di fase per la misura del sar in risonanza magnetica per immagini
No full textDurante un esame diagnostico di Risonanza Magnetica per Immagini, il paziente è sottoposto ad impulsi a radiofrequenza la cui potenza trasmessa si traduce in un riscaldamento dei tessuti. Il SAR (Specific Absorption Rate) è il principale parametro assunto quale riferimento per il controllo degli effetti termici legati ad un’esposizione a radiofrequenza, in quanto utilizzato per una stima dell’incremento di temperatura nei tessuti esposti. Severi limiti ai livelli di SAR sono posti dalle normative per la sicurezza del paziente, sia italiane sia internazionali, ed è fatto obbligo, dalle stesse normative, la misura del SAR per verificarne il rispetto. Il Metodo delle Transizioni di Fase per la Misura del SAR è un metodo innovativo, che utilizza le proprietà delle transizioni di fase per una misura indiretta della potenza assorbita da un oggetto di prova, recipiente contenente una soluzione con proprietà dielettriche e di conducibilità elettrica simili a quelle della regione anatomica di interesse (fantoccio). Esso prevede solo misure di massa e di tempo. La procedura richiede un fantoccio, due tipi di provette con diversa funzionalità ed un sistema di fissaggio del ghiaccio a corredo delle provette, il tutto progettato per l’ottimizzazione del metodo
Metodo per la lavorazione di lamine e giunti elastici sottili, in particolare per la realizzazione di oscillatori meccanici monolitici (METHOD FOR MACHINING THIN PLATES AND ELASTIC JOINTS PARTICULARLY FOR MONOLITHIC MECHANICAL OSCILLATORS )
No full textThe present invention relates to a method for manufacturing thin metal sheets and joints (230J) by removing material from a single block of material (200), i.e. for obtaining items consisting of one or more thin sheets and/or thin elastic joints seamlessly connected to one another by means such as milling. The method can be employed in the manufacturing of a high-sensitivity, low-frequency, broadband monolithic mechanical sensor for measuring linear and angular displacements of based on a folded pendulum configuration for monitoring and control applications
Pendolo ripiegato a bassa frequenza con elevato fattore di qualità meccanico, e sensore sismico utilizzante tale pendolo ripegato
No full textThe invention concerns a folded pendulum, comprising: - a support (F); - a test mass (PM); - a simple pendulum (SP); - an inverted pendulum (IP); the simple pendulum and the inverted pendulum being connected at one of their ends to the test mass (PM) and at the other end to the support (F) by means of 4 corresponding joint systems (G), the test mass being not connected to the support (F) and being therefore free to oscillate, each joint system (G) relevant to the simple pendulum (PS) comprising one or more joints in tension, the folded pendulum being characterised in that: each of the joint systems (G) relevant to the inverted pendulum (IP) comprises one or more joints in compression. The invention further concern a seismic sensor utilizing the folded pendulum according to the invention
Cultural heritage structures and infrastructures vibration monitoring: vibration sensors metrological characteristics identification through finite elements modelling and simulation
No full textThe preservation of historical structures and infrastructures requires a multidisciplinary approach, based on preventive and planned conservation actions. For such a purpose, digital technologies are increasingly used to adaptively model and verify the behavior and stability of heritage assets. However, the reliability of model outputs depends on the accuracy on input data, which, in turn, depends on an appropriate choice of sensors, based on their technical characteristics. This is why an accurate design of monitoring system is crucial. Considering the installation and operation costs for a tailored system, it would be better to understand in advance the expected dynamic response of the structure or infrastructure to fit the monitoring system characteristics to the monitored structure . This is why, this work applies the use of FEM-based simulations to provide preliminary indications on the expected dynamic behavior of a heritage asset, supporting the identification of metrological parameters, in terms of sensors positioning and signals expected features. The used FEM, referred to a prototype of a Doric column, being the scaled 1:5 copy of a marble colonnade of the Temple of Apollo at Bassae (Greece), was designed, reproducing the parameterization (i.e., shape, measures, materials, etc.) of a previous FEM model, implemented and validated on the basis of experimental tests performed at the National Technical University of Athens. The results shed light on optimal sensor positioning and expected signal amplitudes, demonstrating the model's effectiveness in crafting tailored monitoring solutions for preventive conservation. The study underscores the importance of integrating Finite Element Modeling (FEM), avoiding the usual initial parallelization of model design and its experimental validation, into the creation of 'phygital' systems, that blend physical monitoring with digital twins. This approach not only enhances the accuracy of conservation efforts, but also suggests a promising direction for future research aimed at applying this methodology across a diverse range of heritage structures to support proactive preservation strategies
Preliminary design of a vibration monitoring system to be installed in an archaeological heritage structure: The case of the Hera temple (Paestum, S Italy)
No full textDigital models are gaining an increasing popularity for the management of cultural heritage assets. In the context of preventive archaeology, digital models of heritage structures or infrastructures, integrated with a physical counterpart, consisting in a structural monitoring system, can become a phygital system, that can be used to monitor and protect the structural heath of complex and extended assets. Within a mutual optimization process, whose procedure is described here, this work aims to describe how to produce a preliminary vibration monitoring system design configuration, supporting the identification of some relevant metrological parameters of the monitoring systems, in terms of sensors types, their desired technical characteristics and their preliminary positioning, in relation to the measured variable. These preliminary steps are applied to the ancient Greek temple of Hera, located in the UNESCO Paestum-Velia archaeological Park site (Capaccio municipality, Italy)
Vibroacoustic characterization of a chamber music concert room in the context of the urban texture
No full textThe integrated interpretation of the tangible and intangible dimensions of cultural heritage assets is challenging, since much of the required information is often lost or difficult to find. In particular, when coming to the functional planning of historic spaces or archaeological sites, documental or archival sources are scarce or even absent. Consequently, to support the interpretation of these functional design and planning elements, which are related to the life of communities that inhabited those areas, quantitative methods, such as a physical characterization of site-specific environmental variables, may assume a great relevance, like in the case of the vibro-acoustic properties conceived for specific uses or performances, as theatres, cathedrals or other public spaces. With this goal in mind, we have started a pilot experimental activity, aiming at characterizing the vibroacoustic fingerprint, i.e. the vibro-acoustic site-specific features, of a historic building private chamber music concert room, located in the centre of Napoli (South Italy). This work, based on the integration of different sensors and modelling tools, has allowed to observe the site-specific vibroacoustic features not only in relation to the geometric features of the space, but also in relation to the surrounding urban landscape morphology. Consequently, the results have evidenced the presence of a site-specific vibroacoustic fingerprint, related to how the structure and the surrounding urban morphology were planned. The applied integration of a unifying model, previously validated in the literature, and of broadband vibroacoustic measures, has allowed to evidence some quantitative elements, that, characterizing the interaction between spaces and the people living them, constitute a possible basis for interpreting the heritage intangible components (design according to functional and/or symbolic purposes) in relation to different structural urbanistic and architectural elements (tangible heritage)
A new typology of DC tiltmeter based on the Watt's linkage architecture
No full textThe Extended Folded Pendulum Model is a new model aimed at describing the dynamical behavior of a folded pendulum generically oriented in space. This model highlights an analytic relationship between the folded pendulum orientation, referred to the direction of the gravitational acceleration, and its natural resonance frequency. This new feature is the key element for the implementation of high sensitivity stand-alone DC tiltmeters, opening new typologies of application to folded pendulums. In this paper, we present and discuss this model as extension of classical folded pendulum models, using the Tait–Bryan angles formalism. Experimental results obtained with monolithic folded pendulums configured as DC tiltmeters are discussed in connection with the model predictions, also in view of new interesting applications
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