Search results for "passiv"
showing 10 items of 512 documents
Direct evaluation of the equivalent linear damping for TLCD systems in random vibration for pre-design purposes
2014
Abstract Passive control of structural vibrations has received in recent years a great attention from researchers concerned with vibration control. Several types of devices have been proposed in order to reduce the dynamic responses of different kinds of structural systems. Among them, the Tuned Liquid Column Damper (TLCD) proved to be very effective in reducing vibration of structures. Since the increasing use of TLCDs in practical realizations, this paper aims at developing an approximate formulation, by means of a statistical linearization technique, able to estimate the parameters of a structure equipped with a TLCD subjected to random loads for pre-design purposes. Moreover, it is show…
WIDAR: Bistatic WI-fi Detection And Ranging for off-the-shelf devices
2013
The huge spread of wireless networks and the success of location-aware applications require novel indoor po- sitioning mechanisms based on existing technologies such as IEEE 802.11. Taking inspiration from the RADAR, we propose WIDAR: a bistatic WI-fi Detection And Ranging system for off- the-shelf devices. WIDAR implementation is based on the USRP2 platform and is able to locate 802.11 stations while they operate in existing legacy networks. No substitution or repositioning of the Access Points is necessary. WIDAR works passively and does not expect any dedicated action from the target WiFi node. No airtime is wasted and the target cannot even detect that it is being ranged. Such features …
The passive cooling system from tradition to innovation: wind Towers
2012
The work presented by Golnaz Ighany, tutored by Maria Luisa Germanà, is a scheme that shows a synthesis of her PhD Research concluded in March 2011. The aim of the research was exploring the potential of using passive cooling systems and natural ventilation with special attention on wind towers. The study was focused on traditional passive cooling strategies which had been used in Middle East and Mediterranean areas. More particularly, the most common types of wind towers were analyzed in relation to different aspects: from the typology analysis to the dimensional one, from materials to systems and construction processes, from “live welfare” to energy efficiency. In parallel, it was conduct…
Optimal passive-damping design using a decentralized velocity-feedback H-infinity approach
2012
In this work, a new strategy to design passive energy dissipation systems for vibration control of large structures is presented. The method is based on the equivalence between passive damping systems and fully decentralized static velocity-feedback controllers. This equivalence allows to take advantage of recent developments in static output-feedback control design to formulate the passive-damping design as a single optimization problem with Linear Matrix Inequality constraints. To illustrate the application of the proposed methodology, a passive damping system is designed for the seismic protection of a five-story building with excellent results. Peer Reviewed
Étude et manipulation de modes résonants en champ proche optique
2010
Within the quick nano-fabrication techniques evolution and the increasing needs in low space and energy opto-electronic functions on-chip integration, studies and control of electromagnetic resonances of sub-micrometric objects are crucial issues. One aim of this work was then to improve our knowledge of the light-matter interaction. To this end, optical near-field experiments and complementary numerical development of models have been performed to study electromagnetic resonances due to light-matter interaction in sub-micrometric resonators. As an introduction, the first part of the manuscript presents the main phenomena involved in near-field optical microscopy and the used SNOM operation…
The impact of urban contamination on antibioresistance in microbial communities from periphyton and sediments
2020
International audience; Since the early 20's antibiotics have been massively produced and consumed for the benefit of bothhuman and animal health. Nevertheless, antibiotics have also reached the aquatic environmentthrough diffuse sources (e.g. veterinary treatment, contaminated manure application...) and throughwastewater. Consequently, antibiotics concentrations between the ng/L and μg/L range are regularlydetected in surface water and those molecules have also been found in sediments and aquatic biota.The ubiquitous presence of antibiotics exerts a selective pressure on microbial communities leading tothe acquisition and dissemination of antibioresistance in the environment. While both an…
Optimization of Passive Constrained Layer Damping (Pcld) Treatments for Vibration Reduction
2015
An efficient method to reduce the frequency averaged transverse vibration level of aplate by optimizing the position of attached passive constrained layer damping PCLD is presented.This method uses a multilayer anisotropic plate model which is an equivalent single layer platemodel (ESL) where transverse shear stresses and displacements are continuous at each layer’sinterfaces. Hence, for a laminate composed of an arbitrary number of layers, all the quantities arerelated to those of the first layer. The optimization process is based on the use of the ESL platemodel combined with the genetic algorithm (GA) and Latin Hypercube Sampling (LHS) algorithmimplemented in a Rayleigh-Ritz resolution p…
Active and passive recovery influence responses of luteinizing hormone and testosterone to a fatiguing strength loading
2018
The purpose of this study was to examine the acute hormonal and muscular responses to a strenuous strength loading [bilateral leg press (LP) 10x10 1RM] followed by loading-specific active (AR, n = 7, LP 10x10x30% 1RM) or passive (PR, n = 11, seated) recovery. The subjects were men age: 26±4 years, height: 174±8 cm, body mass: 75±13 kg. After control measurements, experimental measurements were conducted at pre and post loading as well as post recovery and next morning. A significantly higher absolute concentration (p<0.05) of serum luteinizing hormone (LH) was observed in AR than PR at next morning while no differences were observed in serum testosterone (T), cortisol (C) or sex hormone bin…
Passive sampling in monitoring of nonylphenol ethoxylates and nonylphenol in aquatic environments
2012
The present practices for determining the concentration levels of various pollutants are in many respects insufficient and for this reason, there is an urgent need especially to develop more cost-effective sampling methods. In this study, a novel passive sampling tool (the Chemcatcher®) for monitoring nonylphenol ethoxylates (NPEOs) and nonylphenol (NP) in aqueous media was tested. These environmentally harmful substances have been widely used in different household and industrial applications and they affect aquatic ecosystems, for example, by acting as endocrine disrupting compounds. The highest accumulation of NPEOs and NP in laboratory-scale tests was obtained when using an SDB-XC (stan…
Le camere dello scirocco: archetipi bioclimatici della Palermo antica
2014
"Scendesi più in basso a man destra vi è una grotta seu camera di scirocco con fontana in mezzo e tutto un giro di mattoni di Valenza e più sopra un lavoro di crocchiole con diversi animali per buttar l’acqua". Queste parole di un atto notarile del 1691 fanno, per la prima volta, riferimento alla 'camera dello scirocco’, singolare esempio di archetipo per il raffrescamento passivo e parte di un inestimabile patrimonio, eredità di secoli di storia e del succedersi di popoli che hanno fatto di Palermo una città d'arte e cultura. Strutture ipogee che, insieme ad altri capolavori di ingegneria presenti nel sottosuolo palermitano, testimoniano quanto le potenzialità dell'ingegno umano siano in g…