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Reaction engineering aspects of polybutylene terephthalate (PBT) polycondensation process
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Aspects of mass transfer in gas-liquid oxidation reactions
Get PDFChemical reactors in which reactants are present in both gas and liquid occur frequently in industry. The study of these type of reactors is quite a challenge in many aspects. Clever design and optimisation increase the profit of the chemical plant, improve safety and reduce the impact on the environment. In design and optimisation activities models are indispensible since large scale experiments are often not feasible and scale-up from lab experiments is required. The majority of models for gas-liquid reactors are based on the twofilm theory, Higbie's penetration theory or by Danckwerts modification
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
Carbon Dioxide Absorption in Piperazine Activated N-Methyldiethanolamine
Get PDFThe removal of carbon dioxide from process gas streams is an important step in many industrial processes for a number of technical, economical or environmental reasons. The conventional technology to capture CO2 on large scale is the absorption - desorption process, in which (aqueous) solutions of alkanolamines are frequently used as solvents [Kohl and Nielsen, 1997]. Nowadays, the addition of an activator, or more specifically piperazine (PZ) to an aqueous N-methyldiethanolamine (MDEA) solution has found widespread application in the bulk removal of carbon dioxide. The principle of such a blend of a primary or secondary (alkanol)amine and a tertiary alkanolamine is based on the relatively high rate of reaction of CO2 with the primary or secondary alkanolamine combined with the low heat of reaction of CO2 with the tertiary alkanolamine, which leads to higher rates of absorption in the absorber column and lower heats of regeneration in the stripper section
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
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