1,721,070 research outputs found
Fabrication and preliminary assessment of a fiber optic-based relative humidity sensor for application in mechanical ventilation
No full textDuring mechanical ventilation, specific devices are used to heat and to humidify gases delivered by mechanical ventilators. Basically, they must replace the function of the upper airways that are bypassed by tracheostomy or endotracheal tubes. Among others heated wire humidifiers (HWHs) are the most popular to accomplish this task. Their control is not based on the measure of relative humidity (RH) but on the gas temperature in a single point of the breathing circuit. Owing to the mentioned control, HWHs' performance shows some weaknesses in particular when they work under demanding ventilatory settings. Moreover, also environmental conditions (e.g., temperature) can affect HWHs' performance. The direct control of the air humidity may be beneficial to overcome these hurdles. The aim of this work is to develop a fiber optic sensors, based on fiber Bragg grating (FBG) technology for RH measurements in mechanical ventilation. It consists of a coated FBG, whose output changes with RH due to the volume expansion of the coating material. The proposed sensor has been fabricated with a simple coating procedure and it is coated with a cost effective polymer (i.e., agarose), which can be used in a wide range of RH values. An experimental set-up allowing the delivering of air with different amounts of vapour content (relative humidity from about 0% to saturation) has been prepared to perform a preliminary assessment of the sensor in a wide range of RH values. The proposed sensor shows promising results in terms of both capability to follow RH changes, as well as sensitivity and range of measurement. Future testing will assess in depth the metrological properties of the proposed sensor and will evaluate the potential of the sensor for RH monitoring during mechanical ventilation. The implementation of a feedback based on RH may be useful both to improve the performance of HWHs, to minimize the influence of external factors on the humidification process, as well as to pave the way to new strategy of control in this field. © 2017 IEEE
Synthesis and properties of p-nitrophenylacetylene-phenylacetylene copolymers
No full textCopolymers of phenylacetylene (PA) and p-nitrophenylacetylene (pNPA) with various monomers ratios were prepared and characterized. The solubility of copolymers is dependent on the number of PA units in the chain. They show a good degree of stereoregularity and the (M) over bar(w)s are in the 10(3)-10(5) a.m.u. range, depending on the monomers and catalyst molar ratios. The soluble samples exhibit film-forming properties and the film-surface morphology may be varied by using different solvents. The copolymers give good electrical response to relative humidity variations
An outlook on the potential of Si nanocrystals as luminescent probes for bioimaging
No full textSilicon nanocrystals (Si-nc) present several plus points as advanced fluorescent biomarkers but suffer from difficulties met in controlling their intrinsic photoluminescence (PL). Here, we first consider the reasons for this difficulty, showing results that support an interface defect-related origin of the PL. Attainment of a controlled PL emission would then require tuning of defects in the capping oxide, a hard and yet unaddressed task. Alternatively, we demonstrate the possible use of Si-nc as antennas, or sensitizers, of a luminescent rare-earth ion in an engineered fluorophore. In this approach the relatively high and broadband optical absorption of Si-nc was exploited, keeping the advantages of a near-infrared inorganic light emitter. Another fundamental part of the assessment of Si-nc for bioimaging is their biocompatibility. Here, we report toxicity tests based on the lactate dehydrogenase release and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assays on epithelial cells and fibroblasts, confirming that Si-nc in concentration suitable for luminescent labeling do not affect significantly the cells viability. © Materials Research Society 2012
Worshop Ricerca, sviluppo e applicazioni per i Beni Culturali. Dai risultati del progetto VADUS alle future collaborazioni. Centro Ricerche ENEA Frascati 9-10 maggio 2023
No full textQuesto volume raccoglie le memorie del workshop “Ricerca, sviluppo e applicazioni per i Beni Culturali. Dai risultati del progetto VADUS alle future collaborazioni” che si è svolto a Frascati il 9 e il 10 maggio 2023 e rappresenta un ottimo strumento di divulgazione per i progetti e le attività in corso in ENEA sul tema della salvaguardia, tutela e cura del patrimonio culturale. Sono qui, quindi, presentate le soluzioni tecnologiche innovative, i prototipi high-tech e le infrastrutture di eccellenza che l’Agenzia mette a disposizione di musei, soprintendenze, istituzioni culturali e piccole e medie imprese per la diagnostica, la conservazione e la valorizzazione del patrimonio culturale e paesaggistico italiano. Con questo volume si vuole mettere a fattore comune il lavoro portato avanti da tutti i dipartimenti ENEA a beneficio sia del processo di comunicazione e collaborazione interna che dell’avvio di azioni sinergiche per affrontare nuove sfide e per la preparazione di nuovi percorsi progettuali competitivi da proporre a livello nazionale ed europeo. L’entusiastica partecipazione e il contributo di tutti i colleghi hanno permesso di arrivare al successo dell’evento e alla realizzazione di questo volume e, pertanto, a loro vanno i più sentiti ringraziamenti. Ai quali si aggiungono quelli rivolti ai numerosi ospiti e alle prestigiose istituzioni che sono intervenute alla discussione, avviando nuovi interessanti canali di comunicazione e collaborazione. Tra questi, il Museo Nazionale Etrusco di Villa Giulia, Il Museo Egizio di Torino, il Parco Archeologico di Ostia Antica, la Soprintendenza per la provincia di Viterbo e l’Etruria meridionale
Probing Delocalisation Across Highly Ethynylated Mono and Dinuclear Pt(II) tethers Containing Nitrogroups and Organic Models as Redox Active Probes. X-ray crystal structure of trans-[Pt(C=C-C6H4NO2)2(PPh3)2]
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Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Study of defect-related light emission in oxidized silicon nanocrystals
No full textLuminescence from surface oxidized silicon nanocrystals (Si-nc) is an intriguing phenomenon with great potential for applications. Full consensus on the source of optical emission is not yet reached despite the huge research effort devoted to this topic. In this paper we report new evidence supporting a defect-related emission mechanism. In particular we propose a defect-based model to interpret the photoluminescence (PL) emission from partially oxidized Si-nc after thermal annealing in air. The PL emission is first studied in the time-dependent regime, using an approach based on discrete light-emitters. The results of this analysis are then exploited for elucidation of continuous wave (CW) data. Using our model the dependence of the PL emission spectrum on the excitation power and the shortening of the time decays at increasing pump power can be explained in terms of the different saturation behavior of luminescent defects. Moreover a rate equation approach for the coupled system composed by the Si-nc core and the associated luminescent defects is used to interpret the luminescence rise-time data under pulsed excitation. In this way the consistency of our picture is verified. Attribution of luminescent defects to non-bridging hole centers combined with oxygen vacancies in the oxide layer capping the Si-nc allows for a preliminary understanding of the increase of luminescence emission intensity and of the variation of its spectral features with the thermal annealing conditions
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
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