1,720,969 research outputs found
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
Projeto de reator fotocatalítico para degradação de poluentes hídricos assistido por CFD e experimentação
No full textTese (doutorado) - Universidade Federal de Santa Catarina, Centro Tecnológico, Programa de Pós-Graduação em Engenharia Química, Florianópolis, 2021.Há décadas a demanda de recursos hídricos tem aumentado devido à expansão populacional e industrial. Juntamente com essa demanda, ocorreu o aumento de contaminantes em águas superficiais e subterrâneas. Dentre esses poluentes, aqueles encontrados em baixas concentrações, e, portanto, emergentes, vêm ganhando foco nas últimas décadas. Isso ocorre por que não existe uma legislação referente à toxicidade desses compostos e a eficiência de remoção por tratamentos convencionais é baixa. O ácido salicílico é um poluente emergente em ascensão, uma vez que é aplicado em produtos de cuidados pessoais e é um metabólito da aspirina. Desta forma, tratamentos alternativos vêm ganhando força no combate aos poluentes emergentes, a exemplo da fotocatálise heterogênea com catalisador imobilizado. Dentro desse contexto, esse trabalho realiza um estudo do processo fotocatalítico com catalisador imobilizado assistido por CFD e experimentação a fim de melhorar a eficiência dos reatores fotocatalíticos na degradação de poluentes hídricos. Para esse estudo foi realizada uma validação prévia dos modelos matemáticos do processo fotocatalítico (equações de Navier-Stokes, equações de transferência de radiação e equações de transferência de massa da espécie química com reação) com dados da literatura. Com intuito de melhorar a capacidade de predição do modelo matemático do processo fotocatalítico, avaliou-se a sensibilidade do número de Schmidt turbulento para sistemas com diferentes resistências à transferência de massa externa utilizando os modelos de turbulência k- e padrão, AKN e RSM. Em seguida, realizou-se a montagem de uma unidade experimental com um reator fotocatalítico diferencial projetado de forma assistida por CFD. A unidade foi desenvolvida para gerar dados experimentais a fim de validar os modelos matemáticos e obter a cinética intrínseca de degradação fotocatalítica do ácido salicílico em fase líquida utilizando TiO2 imobilizado. Antes de realizar a cinética, verificou-se a capacidade do processo fotocatalítico em mineralizar o ácido salicílico, avaliou-se um método de imobilização com boa eficiência de degradação e baixa lixiviação e verificou-se os efeitos da concentração inicial de poluente e da vazão de escoamento frente a eficiência de degradação. O modelo cinético obtido foi utilizado como condição de contorno de parede nas simulações de CFD com intuito de otimizar um reator anular com labirinto por meio de um planejamento estatístico Box Behnken e do método função desejabilidade. Os resultados referentes às validações dos modelos matemáticos laminar e turbulento do processo fotocatalítico fundamentados em dados da literatura mostraram que os mesmos são capazes de predizer os fenômenos de transferência de quantidade de momento, de transferência de massa da espécie química e de transferência da radiação. Com base no estudo de sensibilidade do número de Schmidt turbulento, verificou-se que esse tem um efeito significativo na predição em sistemas com alta limitação à transferência de massa e que o mesmo tem sensibilidade diferente dependendo do modelo de turbulência utilizado. Entre os modelos de turbulência, observou-se que o modelo AKN com Sct igual a 0,8 forneceu a melhor resposta na predição da transferência de massa nos processos fotocatalíticos com alta limitação a transferência de massa. No entanto, o modelo k-e padrão com Sct igual a 0,2 pode ser uma alternativa para simular casos complexos, uma vez que esse modelo apresentou menor custo computacional e maior estabilidade numérica em relação aos demais. Dos experimentos de imobilização, observou-se que o método de imobilização denominado calcinação foi o mais adequado para utilização nos experimentos de degradação do ácido salicílico, uma vez que teve boa eficiência e baixa lixiviação do catalisador. Ainda fundamentado nos experimentos de bancada, concluiu-se que o processo fotocatalítico com TiO2 imobilizado e luz UVC é capaz de realizar não só a degradação, mas também a mineralização do ácido salicílico e que esse processo segue uma cinética de primeira ordem, tanto em relação à concentração quanto em relação à intensidade de luz. Por fim, concluiu-se que a combinação de ferramentas estatísticas e de fluidodinâmica computacional pode ser uma boa alternativa para realização de projetos e otimizações de reatores fotocatalíticos, uma vez que o reator fotocatalítico anular otimizado neste trabalho apresentou um tempo de degradação e um valor energético operacional 53% inferior do que os valores de tempo e energia de um reator anular convencional.Abstract: For decades, the demand for water resources has increased due to population and industrial expansion. Along with this demand, there was an increase in contaminants in surface and groundwater. Among these pollutants, those found in low concentrations, and therefore emerging, have been gaining focus in recent decades. This focus is due to the fact that there is no legislation on the toxicity of these compounds and the removal efficiency by conventional treatments is low. Salicylic acid is an emerging pollutant on the rise, as it is applied in personal care products and it is a metabolite of aspirin. Thus, alternative treatments are gaining power in the fight against emerging pollutants, such as heterogeneous photocatalysis with immobilized catalyst. Within this context, this work carries out a study of the photocatalytic process with immobilized catalyst assisted by CFD and experiments in order to improve the efficiency of photocatalytic reactors in the degradation of water pollutants. For this study, a previous validation of the mathematical models of the photocatalytic process (Navier-Stokes equations, radiation transfer equations and chemical transfer mass equations with reaction) was performed with data from the literature. In order to improve the predictive capacity of the mathematical model of the photocatalytic process, the sensitivity of the turbulent Schmidt number for systems with different resistance to external mass transfer was evaluated using the standard k-e, AKN and RSM turbulence models. Then, an experimental unit was assembled with a differential photocatalytic reactor designed in a CFD-assisted manner. The unit was developed to generate experimental data to validate the mathematical models and obtain the intrinsic kinetics of photocatalytic degradation of salicylic acid in liquid phase using immobilized TiO2. Before performing the kinetics, the capacity of the photocatalytic process to mineralize salicylic acid was verified. Also, the immobilization method, the initial pollutant concentration and the flow rate of the process were verified with aim of obtain a good degradation efficiency and low leaching. The kinetic model obtained was used as a wall boundary condition in CFD simulations in order to optimize an annular reactor with labyrinth through Box Behnken statistical planning and the desirability function method. The results from the validations of the laminar and turbulent mathematical models of the photocatalytic process based on data from the literature showed that they are capable of predicting the phenomena of momentum quantity transfer, chemical mass transfer and radiation transfer. Based on the sensitivity study of the turbulent Schmidt number, it was found that this has a significant effect on the prediction in systems with high limitation to mass transfer and that it has different sensitivity depending on the turbulence model selected. Among the turbulence models, it was observed that the AKN model with Sct equal to 0.8 provided the best response in the prediction of mass transfer in photocatalytic processes with high limitation to mass transfer. However, the standard k-e model with Sct equal to 0.2 can be an alternative to simulate complex cases, since this model presented lower computational cost and greater numerical stability in relation to the others. From the immobilization experiments, it was observed that the immobilization method called calcination was the most suitable for use in degradation experiments of salicylic acid, since it had good efficiency and low leaching of the catalyst. Still based on bench experiments, it was concluded that the photocatalytic process with immobilized TiO2 and UVC light is capable of performing not only the degradation, but also the mineralization of salicylic acid and that this process follows a first order kinetics, both in relation to concentration as to light intensity. Finally, it was concluded that the combination of statistical tools and computational fluid dynamics can be a good alternative to perform projects and optimizations of photocatalytic reactors, since the annular photocatalytic reactor optimized in this work presented a degradation time and an energy value operational 53% lower than the time and energy values of a conventional annular reactor
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
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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