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Projeto e desenvolvimento de uma bancada didática de testes para análise de troca térmica e estabilidade do sistema de controle
Get PDFThis work describes a didactic test rig both for simulation of a control system
and for studies thermal exchange in a shell and tube type heat exchanger enabling
simulation of several configuration of flow currents. Another aspect and purpose of the
test rig is the possibility to study and analysis of the dynamic behavior of the heat
exchanger temperature control using a frequency inverter as final control element
instead of the conventional control valves for controlling the flow rate. Several
temperature measurements in the inlets and outlets of the heat exchanger have been
executed, allowing the obtainment of the overall heat transfer coefficients for concurrent
and countercurrent flows. These results were compared with the theoretical ones
calculated with the heat exchanger dimensions, fluid and flows characteristics. Related
to the control system, a temperature control optimization has been executed by using the
Ziegler-Nichols limit sensitivity of tunning method. Using the graphic resources of the
used supervisory software, the static and dynamic characteristics of the process were
obtained for the elaboration of the system mathematical model and than the simulation
with the Simulink software, were made, using the same tunning method. An analysis of
the results have shown a good agreement between experiments and theory for both the
thermal and the control viewpoint. An analysis of the obtained results is presented
showing good agreement between the experimental and theoretical approach for both
thermal and control system treatment. Also, some suggestions for future studies
exploring the available and possible resources of the test rig are presented.Este trabalho apresenta uma bancada didática de testes para uso tanto em
simulação de controle como para estudo da troca térmica, através de um trocador de
calor do tipo casco e tubos, possibilitando diversas configurações de correntes de fluxo.
Outra finalidade do sistema é o estudo e análise do comportamento dinâmico do
controle de temperatura do trocador, utilizando como elemento final de controle um
inversor de freqüência na manipulação na vazão, substituindo o estrangulamento do
fluxo provocado por válvulas de controle convencionais. Foram efetuadas diversas
medições de temperatura nas entradas e saídas do trocador, permitindo a obtenção do
coeficiente global de transferência de calor para os escoamentos concorrente e
contracorrente. Os valores obtidos foram comparados com os valores calculados a partir
das características do trocador, do fluido e do escoamento. No sistema de controle, foi
efetuada a otimização do controle de temperatura aplicando o método de sintonia da
sensibilidade limite de Ziegler-Nichols. Empregando-se os recursos gráficos do
software supervisório utilizado, foram obtidas as características estáticas e dinâmicas do
processo para elaboração do modelo matemático do sistema, sendo então feita a
simulação com o software Simulink utilizando o mesmo método de sintonia. É
apresentada uma análise dos resultados obtidos evidenciando a aproximação entre os
resultados teóricos e práticos do sistema térmico e do sistema de controle, assim como
sugestões para futuros estudos explorando os recursos disponíveis e possíveis do
sistema
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
Variations 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
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
Author Under Sail The Imagination of Jack London, 1893-1902
No full textIn Author Under Sail, Jay Williams offers the first complete literary biography of Jack London as a professional writer engaged in the labor of writing. It examines the authorial imagination in London's work, the use of imagination in both his fiction and nonfiction, and the ways he defined imagination in the creative process in his business dealings with his publishers, editors, and agents. In this first volume of a two-volume biography, Williams traverses the years 1893 to 1902, from London's "Story of a Typhoon" to The People of the Abyss. The Jack London who emerges in the pages of Author Under Sail is a writer whose partnership with publishers, most notably his productive alliance with George Brett of Macmillan, was one of the most formative in American literary history. London pioneered many author models during the heyday of realism and naturalism, blurring the boundaries of these popular genres by focusing on absorption and theatricality and the representation of the seen and unseen. London created an impassioned, sincere, and extremely personal realism unlike that of other American writers of the time. Author Under Sail is a literary tour de force that reveals the full range of London as writer, creative citizen, and entrepreneur at the same time it sheds light on the maverick side of machine-age literature.Intro -- Title Page -- Copyright Page -- Dedication -- Contents -- Acknowledgments -- Introduction -- 1. Spirit Truth -- 2. From Absorption to Theatricality and Back Again -- 3. "I Will Build a New Present" -- 4. Sons as Authors -- 5. Fathers as Publishers -- 6. The Daughter as Author -- 7. Lovers as Authors -- 8. At Sea with the Family -- 9. Yellow News, Yellow Stories -- 10. The Return Home -- Notes -- Bibliography -- Index -- About Jay WilliamsIn Author Under Sail, Jay Williams offers the first complete literary biography of Jack London as a professional writer engaged in the labor of writing. It examines the authorial imagination in London's work, the use of imagination in both his fiction and nonfiction, and the ways he defined imagination in the creative process in his business dealings with his publishers, editors, and agents. In this first volume of a two-volume biography, Williams traverses the years 1893 to 1902, from London's "Story of a Typhoon" to The People of the Abyss. The Jack London who emerges in the pages of Author Under Sail is a writer whose partnership with publishers, most notably his productive alliance with George Brett of Macmillan, was one of the most formative in American literary history. London pioneered many author models during the heyday of realism and naturalism, blurring the boundaries of these popular genres by focusing on absorption and theatricality and the representation of the seen and unseen. London created an impassioned, sincere, and extremely personal realism unlike that of other American writers of the time. Author Under Sail is a literary tour de force that reveals the full range of London as writer, creative citizen, and entrepreneur at the same time it sheds light on the maverick side of machine-age literature.Description based on publisher supplied metadata and other sources.Electronic reproduction. Ann Arbor, Michigan : ProQuest Ebook Central, YYYY. Available via World Wide Web. Access may be limited to ProQuest Ebook Central affiliated libraries
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