1,720,956 research outputs found
Optimal management and data-based predictive control of district heating systems: The Novate Milanese experimental case-study
No full textThis paper addresses the modelling and optimal control of district heating systems connected to the electrical grid, with the goal of maximizing their operational efficiency and enabling the participation to electricity markets. Being these systems governed by nonlinear large-scale dynamical models, a novel procedure is proposed, which enables to obtain suitable models for optimization, and consisting in a combination of physical and identified piece-wise linear models. A two-phase optimization and control scheme is then designed, including an offline scheduling problem for participating to the day-ahead energy market, and an online Model Predictive Control system, minimizing the energy consumption of thermal generators while properly satisfying the users thermal demand. The proposed methodology is developed considering a real district heating plant, owned by the energy company A2A S.p.A. and supplying the city of Novate Milanese (Italy), and different experiments on the plant have been carried out. The experimental results and achieved performances are promising, showing a significant reduction of the operational costs and overall gas consumption
Experiments on aerosol removal by high-pressure water spray
No full textAn experimental research was managed in the framework of the PASSAM European Project to measure the efficiency of high-pressure sprays in capturing aerosols when applied to a filtered containment venting system in case of severe accident. The campaign was carried out in a purposely built facility composed by a scrubbing chamber 0.5 × 1.0 m and 1.5 m high, with transparent walls to permit the complete view of the aerosol removal process, where the aerosol was injected to form a cloud of specific particle concentration. The chamber was equipped with a high pressure water spray system with a single nozzle placed on its top. The test matrix consisted in the combination of water pressure injections, in the range 50–130 bar, on a cloud of monodispersed SiO2 particles with sizes 0.5 or 1.0 μm and initial concentration ranging between 2 and 99 mg/m3. The spray was kept running for 2 min and the efficiency of the removal was evaluated, along the test time, using an optical particle sizer. With respect to low-pressure sprays, the removal efficiency turned out much more significant: the half-life for 1 μm particles with a removal high-pressure spray system is orders of magnitude shorter than that with a low-pressure spray system. The highest removal rate was detected with 1 μm particles at the highest water injection pressure, mainly because of the high concentration of droplets with high velocity, while lower removal was measured for 0.5 μm particles. No influence of the initial aerosol concentration was observed for both particle sizes
Experimental studies and modeling of a high pressure spray system for aerosol decontamination
Full text linkLAUREA MAGISTRALEIn caso di grave incidente nelle centrali nucleari, i prodotti di fissione possono essere rilasciati sotto forma di aerosol. Gli spray attualmente utilizzati come sistemi di sicurezza nelle centrali as acqua leggera (LWR) sono stati principalmente dimensionati per sopprimere la pressurizzazione del vapore durante incidenti base dovuti alla perdita di refrigerante, per rimuovere lo iodio molecolare dall'atmosfera di contenimento e per migliorare la miscelazione dei gas in caso di presenza di idrogeno.
Il progetto europeo PASSAM si propone di studiare le prestazioni degli attuali sistemi di mitigazione e di valutare la possibilità di valutare altri sistemi innovativi da poter usare nelle attuali e future centrali nucleari.
Questo lavoro sviluppato presso RSE spa ha lo scopo di mettere in evidenza le prestazioni di decontaminazione degli spray ad alta pressione e di sviluppare un modello semplificato per prevederne il tasso di rimozione di aerosol.
Tutta l'attività è stata sviluppata in tre parti. Le prime due sono di natura sperimentale e hanno lo scopo di ottenere i dati rigurdanti sia le prestazioni di decontaminazione che le caratteristiche degli spray ad alta pressione. L'ultima parte è quella di condensare le conoscenze teoriche e i dati sperimentali per sviluppare il modello di previsione.In case of severe accident in nuclear power plants, fission products can be released under the form of aerosol particulate. The current sprays used as safety systems in Light Water Reactor (LWR) were mainly dimensioned to suppress steam pressurization during design basis loss-of-coolant accidents, to remove molecular iodine from the containment atmosphere and to enhance the gas mixing in case of the presence of hydrogen.
The European PASSAM project is aimed to study the performances of current mitigation systems and to evaluate the possibility of other innovative systems to be implemented in the current and future nuclear power plants.
This work developed at RSE spa has the aim to put in evidence the decontamination performances of the high pressure sprays and to develop a simplified model to predict their aerosol removal rate.
The whole activity has been developed in three parts. The first two are of experimental nature and are aimed to obtain data of both the decontamination performances and characteristics of the high pressure water spray. The last part is to condense theoretical knowledge and experimental data to develop a model that may provide good approximations of the spray behaviour
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
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
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
- …
