1,720,954 research outputs found
Dynamic behaviour of a hybrid steam generator equipped with a gate valve
No full textCogeneration is an often viable and efficient solution to cover combined demands of electric and thermal power, especially when the demand of the latter remains fairly constant over time. The efficient use of energy and the economic advantages that are associate to it have made cogeneration the solution of choice in many industrial applications, among which paper mills represent a significant share. The heat recovery steam generator often has an auxiliary burner to ensure full coverage of the thermal load in all operating conditions. In order to reduce installation and conduction costs, the combustion chamber may lack an extraction fan, which has the drawback that pressure varies according to changes in the loads, and this affects the stability of the flame adversely. In order to ensure constant pressure in the combustion chamber, application of a gate valve downstream of the heat recovery steam generator is proposed. A lumped-parameter model is set up in Simulink® and the feedback loop tested for to sudden variations in the thermal power required by the paper mill, mainly due to variations in the number of operating machines, and to failure of the internal combustion engine. It is demonstrated that the gate valve is necessary and that the use of a PID feedback control system ensures a constant pressure in the combustion chamber
Dynamic Modelling of a Heat Exchanger Network for a Dairy Plant
Full text linkIn co-and trigeneration plants with internal combustion engines, waste heat from their cooling system can be fed to a heat exchanger network for office heating, hot water production, or used in industrial processes. At the same time, care must be exerted not to cool the return fluid below a threshold, in order to avoid piston seizure. In this work, the heat exchanger network is that of a gas-engine trigeneration system for a large dairy plant in Rome. Since its daily and weekly production schedule is subject to several changes, temperature control must be both precise and efficient. A thermal-hydraulic, dynamic (i.e. time-dependent) model of the heat exchanger network was developed in Matlab/Simulink, to obtain the instantaneous pressure, mass flowrate and temperature of the fluids along the network. The approach is mixed, a lumped-parameter description of the hydraulic and thermal networ, and finite volumes for the heat exchangers. The model has been verified and validated with experimental, steady-state data from the dairy plant and the results found satisfactory
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
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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