1,721,082 research outputs found
Effect of the contact tank geometry on disinfection efficiency
No full textDisinfection is a sanitary treatment present in both drinking water and wastewater treatment plants aimed at removing pathogenic microorganisms able to damage the human health. The focus of this study is to apply Computational Fluid Dynamics (CFD) to study and to improve the disinfection efficiency through the optimization of the hydrodynamics inside the disinfection tank. Numerous literature studies have shown that water flow inside traditional multichamber tanks is highly turbulent because of the development of large as well as small vortices in which flow velocity decreases or even vanishes (dead zones). These turbulent phenomena are responsible of an increase of the real residence time, compared to the theoretical one, causing poor disinfection and the development of unwanted by-products. In the present analysis, Large Eddy Simulation (LES) is used to simulate three-dimensional turbulent flow and disinfectant transport in different contact tanks using a structured finite-volume discretization. The results show how the baffles' geometry, as well as the design of technical and construction details, influences the hydraulic retention time of the disinfectant, varying the disinfection efficiency. In particular, the creation of horizontal baffles inside the vertical baffle chambers reduces the free space and extends the flow path. This reduces both short circuits and recirculation zones bringing the flow closer to the ideal plug-flow condition
Unidirectional Direct Load Control through Smart Plugs
No full textBalancing energy demand and production is becoming a more and more challenging task for energy utilities also because of the larger penetration of renewable energies which are more difficult to predict and control. While the traditional solution is to dynamically adapt energy production to follow time-varying demand, a new trend is to drive demand itself. Most of the ongoing actions in this direction involve greedy energy consumers, like industrial plants, supermarkets or large buildings. Pervasive communication technologies may allow in the near future to push further the granularity of such approach, by having the energy utility interacting with residential appliances. In this paper we study large scale direct control of inelastic home appliances whose energy demand cannot be shaped, but simply deferred. Our solution does not suppose any particular intelligence at the appliances. The actuators are rather \emph{smart plugs}---simple devices with local communication capabilities that can be inserted between appliances' plugs and power sockets and are able to interrupt/reactivate power flow through the plug.
A simple control message can be broadcast to a large set of smart plugs for probabilistically enabling or deferring the activation requests of a specific load type in order to satisfy a probabilistic bound on the aggregated power consumption. The control law can be easily derived analytically
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Bench scale continuous coagulation-flocculation of saline industrial wastewater contaminated by hydrocarbons
No full textThis study analyzes the outcomes obtained with the treatment of coagulation-flocculation applied to industrial wastewater coming from an oil tanker. Characteristics of this wastewater are high salinity and the presence of recalcitrant pollutants predominantly of hydrocarbon origin. Therefore, the application of a chemical-physical treatment is preferred rather than biological treatment, since the simultaneous effect of salinity and hydrocarbons plays an inhibitory role in biomass growth. In coagulation-flocculation process, the first phase of coagulation aims at electrical destabilization of pollutants particles, whereas the flocculation phase allows destabilized particles to aggregate and form flakes which, then, the last phase of the process removes from effluent by sedimentation or flotation. The novelty of this experimentation consists in the optimization of the continuous wastewater treatment with advantages both economic and in terms of treatment flexibility. The observation of the continuous process has highlighted the need for a deflector element in the passage section from the flocculation to the sedimentation compartment, to guarantee the establishment of the calm conditions necessary to allow sedimentation inside the last compartment. Results' analysis has shown that the process allows high removal efficiencies of the main pollutants analyzed in this study. In particular, the removal efficiency of TSS always stood at values greater than 90 %, while the removal efficiency of TPH was even almost close to 100 %. Instead, the removal of the organic substance in terms of COD and TOC has achieved lower performances. Therefore, in the outlet wastewater the levels of the contaminants were usually lower than the limits imposed by law to allow the discharge into the receiving water body (sea). The best test was the one in which the slop fed to the system of coagulation-flocculation was previously subjected to a treatment in which the oil was removed. Furthermore, the presence of the deflector element favors the sludge settling and therefore the removal of pollutants from the clarified
Q-wave prediction of myocardial infarction location, size and transmural extentat magnetic resonance imaging
No full textVariations on the Author
Get PDF“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
Get PDFWe 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
Get PDFWe 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
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