2,544 research outputs found
Il liberalismo di Nicola Matteucci. Con bibliografia degli scritti.
No full textQuesto volume ricostruisce, attraverso vari interventi di storici del pensiero e delle istituzioni politiche e filosofi politici, l'attività di studio e di pensiero di Nicola Matteucci. Il volume contiene inoltre la bibliografia completa dei suoi scritti, sia di quelli appartenenti alla sua attività prettamente scientifica, sia degli articoli, interventi vari e interviste pubblicati sui quotidiani. Nel complesso il volume, pubblicato un anno dopo la sua scomparsa, ripropone la complessa figura dello studioso, del pensatore politico e dell'intelletuale civilmente impegnato nel dibattito politico italiano della seconda metà del sec. XX e nel primo scorcio del sec. XXI
Author Meets Reader: Not the Marrying Kind: A Feminist Critique of Same-Sex Marriage
No full textThis is an audio recording of an author meets reader session held at the SLSA Annual Conference, University of York, 27 March 2013. Nicola Barker's book, Not the Marrying Kind: A Feminist Critique of Same-Sex Marriage, was the winner of the 2013 Hart SLSA Book Prize. In the session she introduces the book and then engages in discussion about it with Daniel Monk
South Thompson Valley and Pinantan official settlement plan.
No full textThe recommended policies contained in this plan provide the Thompson-Nicola Regional District with the means to protect and enhance the agricultural economic base, regulate the supply and location of rural residential growth, guide commercial and industrial development and satisfy the historical, recreational, social and environmental concerns of the settlement plan area.Not peer reviewedPlanning documen
Rural Residential Study
No full textThe Thompson-Nicola Regional District has recently been grappling with some of the basic problems and conflicts of trying to provide for rural residential lot demand and, at the same tie, trying to protect the resources, aesthetics and social climate of existing rural area.Not peer reviewedstudydraf
A novel shaped piezoelectric sensor for impact localization in plate structures
No full textImpact localization in plate-like structures by means of Lamb waves is an important task in structural health monitoring applications. Passive-only networks of piezoelectric wafer active sensors (PWAS) can be exploited to this aim. In this work, a novel piezoelectric sensor for guided wave detection on laminate composite and metallic structures is presented. Such device is capable of revealing the direction of the incoming waves thanks to its peculiar shape. A small footprint, low power, and light weight sensor node was also implemented. This device is meant as a basic building block for smart structure passive sensor networks development. Elastic waves generated from impacts and propagating on the structure are recorded by the shaped transducer and then processed by a microcontroller embedded on the sensor node. The effectiveness of the proposed technology was assessed with an experimental validation
A small footprint, low power, and light weight sensor node and dedicated processing for modal analysis
No full textStructural Health Monitoring functionalities are aimed at constantly assessing the health of a building in order to prevent dramatic consequence of a damage. This work describes a well-defined wireless sensor network system installed over a steel beam capable to perform modal parameters estimation, such as natural vibration frequencies and modal shapes. Signal Processing Techniques were aimed at computing Power Spectral Density of the acceleration signals acquired, dealing with parametric and non parametric approaches. Algorithms in frequency domain, together with the Second Order Blind Identification method were implemented for modal shapes reconstruction. Beside a satisfactory agreement between the theoretical model and the output response of the algorithms implemented, versatility, easiness of reconfiguration, scalability and compatibility with long term installation are among the most powerful advantages of the architecture proposed. Light weight, low power consumption also enhance the capabilities of the system to provide real-time information in a relatively cheap way
Piezo-transducer's shape design as a pre-processing tool in guided wave inspections
No full textStructural health monitoring is an important task in several industrial applications. For example, passive-only networks of piezoelectric sensors can be exploited to detect and localize impacts or anomalous acoustic emissions for the early identification of crack initiation and growth from the analysis of the emitted ultrasonic guided waves. In this work, a shaped piezoelectric sensor and the dedicated electronics for guided wave detection on laminate composite and metallic structures is presented. This device is meant as a basic building block for the development of passive sensor networks in smart structure applications. Elastic waves propagating on the structure are recorded by the transducer composed by multiple, irregularly shaped electrodes and then processed by a microcontroller embedded on the sensor node. The irregular shaping of the transducer electrodes is exploited to simplify the signal processing procedures that are necessary to detect the wave direction of arrival
A design strategy for highly directional piezoelectric transducers for Lamb waves inspections
No full textDrastic hardware simplification and cost reduction of Guided Waves (GWs) based systems can be achieved by using shaped transducers that present inherent directional capabilities when generating and sensing elastic waves. Directional transducers for GW generation and sensing are achieved by patterning the piezoelectric material lay-out and the electrodes. The peculiar electrodes’ shape produces a spatial filtering effect which is frequency-dependent,
so that a direct relationship can be established between the direction of propagation (wavenumber) and the spectral content of the transmitted/received signal. This kind of transducer has been named Frequency Steerable Acoustic Transducers (FSATs). In this work, a transducer’s shape design strategy is presented which is able to enhance the
accuracy of the desired Directivity function approximation. The proposed design strategy is based on Dithering techniques. The effectiveness of the novel transducer design methodology is shown through a numerical validation with application to defect detection in an aluminum plate
Metodi e tecnologie per ispezioni con onde ultrasoniche guidate di piastre e gusci in composito
No full textTra le tecnologie proposte per il monitoraggio strutturale (in inglese Structural Health Monitoring o SHM), quelle che usano onde ultrasoniche guidate sono considerate tra le più promettenti e versatili per le applicazioni che riguardano i materiali compositi. Con onde guidate ci si riferisce ad onde meccaniche che si propagano in strutture o in elementi strutturali, le guide d’onda, con almeno una dimensione caratteristica paragonabile alla lunghezza d’onda delle onde stesse. L’interazione tra la lunghezza d’onda e la geometria della guida d’onda dà luogo all’esistenza di svariate onde meccaniche. Tali onde variano in numero e mutano le loro caratteristiche di propagazione quali lunghezza d’onda, velocità, attenuazione e forma d’onda, al variare della frequenza (comportamento dispersivo).
Le implementazioni tipiche di questi sistemi prevedono un sistema software/hardware che controlla una rete di trasduttori piezoelettrici posti sulla struttura da controllare, attraverso i quali si generano e ricevono onde guidate che sondano la struttura stessa. Mediante procedure di analisi dei segnali registrati ai trasduttori, le metodologie cercano di risalire allo stato di integrità del componente.
La concreta possibilità di integrare una simile tecnologia di monitoraggio ad onde guidate in strutture in composito è attualmente limitata da: (i) scarsità di strumenti per la modellazione della propagazione in materiale composito; (ii) ingombro della strumentazione e cablature non compatibili con il monitoraggio permanente; (iii) limitata validazione delle tecnologie in condizioni operative ambientali (iv) elevati costi di integrazione. Per superare queste limitazioni sono allo studio nuovi trasduttori piezoelettrici e tecniche avanzate di elaborazione di segnale
Frequency Steerable Transducers with 360° Directivity for Guided Waves Inspections in Plate-like Structures
No full textDirectional Transducers for Guided Waves generation and sensing are achieved by patterning the piezoelectric material lay-out and the electrodes. The peculiar electrodes’ shape produces a spatial filtering effect which is frequency-dependent, so that a direct relationship can be established between the direction of propagation (wavenumber) and the spectral content of the transmitted/received signal. This kind of transducer has been named Frequency Steerable Acoustic Transducers (FSATs). FSAT dedicated signal processing algorithms enable localization of acoustic events in 2D spaces by processing two differential output of a single device, i.e. using only two acquisition channel thus allowing for a drastic hardware simplification and cost reduction of Guided wave based systems. In this work, a new generation of FSATs is proposed, which allows steering the wave direction of propagation in the whole angular range [0°; 360°] with improved directivity and sidelobes reduction
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