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Xylene isomers sorption on zeolite beta
Get PDFMestrado de dupla diplomação com a University of SaidaThe separation of C8 alkylaromatic mixed compounds is an important process in the chemical industry due to its direct connection with the manufacturing of PET (Polyethylene Terephthalate).The separation can be performed by distillation but the similarity of its boiling points increase significantly the cost. Alternatives are the crystallization and adsorption. In this work it is studied the ability of zeolite BETA to adsorb xylene isomers as a possible alternative adsorbent to the commonly used Faujasite zeolite or Y zeolite in the so called adsorptive process.
Zeolite BETA is an intergrowth of two or three polymorphs of crystalline microporous materials formed by tetrahedral corner-sharing TO4 (T = Si or Al) in a unique porous structure with fine thermal and chemical stability. They have found wide spread applications in many industrial field such as catalysis, adsorption, separation, and ion exchange.
In this work it is studied the application of Zeolite BETA to separate xylene isomers in vapor phase by adsorption, through an experimental study to determine single component adsorption equilibrium isotherms of xylene isomers and ethylbenzene between the temperatures ranges from 125 to 175ºC. The results obtained in this work are important for further studies in multicomponent systems regarding the ability of zeolite BETA to separate xylene isomers.
The adsorbed amount is higher at the lower temperature (125 °C) with values around 0.8 g/100gads and decrease with the increase temperature (175 °C).The adsorption hierarchy order is: EB > OX > PX> MX . The selectivity is very low but we could improve it with decrease the temperature.A separação dos compostos alquilaromáticos C8 é um processo importante na indústria química devido à sua ligação directa com o fabrico de PET (Polietileno Tereftalato). A separação pode ser feita por destilação - mas a semelhança dos seus pontos de ebulição aumenta significativamente o custo. As alternativas são a cristalização e a adsorção. Neste trabalho é estudada a capacidade do zeólito BETA de adsorver isómeros de xileno como possível adsorvente alternativo ao zeólito Faujasite ou zeólito Y comummente utilizado no chamado processo adsorvente.
O zeólito BETA é um intercrescimento de dois ou três polimorfos de materiais microporosos cristalinos formados por tetraédricos de partilha de cantos TO4 (T = Si ou Al) numa estrutura porosa única com estabilidade térmica e química fina. Encontraram aplicações generalizadas em muitos campos industriais tais como a catálise, adsorção, separação e troca iónica.
Neste trabalho é estudada a aplicação do zeólito BETA para separar isómeros de xileno em fase de vapor por adsorção, através de um estudo experimental para determinar isómeros de isómeros de xileno e etilbenzeno em equilíbrio de adsorção de componente único entre as temperaturas de 125 a 175ºC. Os resultados obtidos neste trabalho são importantes para estudos adicionais em sistemas multicomponentes relativamente à capacidade do zeólito BETA de separar os isómeros de xileno.
A carga adsorvida é maior à temperatura mais baixa (125 °C) com valores em torno de 0,8 g/100gads e diminui com a temperatura (175 °C): EB > OX > PX> MX. A selectividade é vista como muito baixa, mas pode mos dizer que quando a temperatura diminui
Xylene isomers sorption on zeolite beta
No full textMestrado de dupla diplomação com a University of SaidaThe separation of C8 alkylaromatic mixed compounds is an important process in the chemical industry due to its direct connection with the manufacturing of PET (Polyethylene Terephthalate).The separation can be performed by distillation but the similarity of its boiling points increase significantly the cost. Alternatives are the crystallization and adsorption. In this work it is studied the ability of zeolite BETA to adsorb xylene isomers as a possible alternative adsorbent to the commonly used Faujasite zeolite or Y zeolite in the so called adsorptive process.
Zeolite BETA is an intergrowth of two or three polymorphs of crystalline microporous materials formed by tetrahedral corner-sharing TO4 (T = Si or Al) in a unique porous structure with fine thermal and chemical stability. They have found wide spread applications in many industrial field such as catalysis, adsorption, separation, and ion exchange.
In this work it is studied the application of Zeolite BETA to separate xylene isomers in vapor phase by adsorption, through an experimental study to determine single component adsorption equilibrium isotherms of xylene isomers and ethylbenzene between the temperatures ranges from 125 to 175ºC. The results obtained in this work are important for further studies in multicomponent systems regarding the ability of zeolite BETA to separate xylene isomers.
The adsorbed amount is higher at the lower temperature (125 °C) with values around 0.8 g/100gads and decrease with the increase temperature (175 °C).The adsorption hierarchy order is: EB > OX > PX> MX . The selectivity is very low but we could improve it with decrease the temperature.A separação dos compostos alquilaromáticos C8 é um processo importante na indústria química devido à sua ligação directa com o fabrico de PET (Polietileno Tereftalato). A separação pode ser feita por destilação - mas a semelhança dos seus pontos de ebulição aumenta significativamente o custo. As alternativas são a cristalização e a adsorção. Neste trabalho é estudada a capacidade do zeólito BETA de adsorver isómeros de xileno como possível adsorvente alternativo ao zeólito Faujasite ou zeólito Y comummente utilizado no chamado processo adsorvente.
O zeólito BETA é um intercrescimento de dois ou três polimorfos de materiais microporosos cristalinos formados por tetraédricos de partilha de cantos TO4 (T = Si ou Al) numa estrutura porosa única com estabilidade térmica e química fina. Encontraram aplicações generalizadas em muitos campos industriais tais como a catálise, adsorção, separação e troca iónica.
Neste trabalho é estudada a aplicação do zeólito BETA para separar isómeros de xileno em fase de vapor por adsorção, através de um estudo experimental para determinar isómeros de isómeros de xileno e etilbenzeno em equilíbrio de adsorção de componente único entre as temperaturas de 125 a 175ºC. Os resultados obtidos neste trabalho são importantes para estudos adicionais em sistemas multicomponentes relativamente à capacidade do zeólito BETA de separar os isómeros de xileno.
A carga adsorvida é maior à temperatura mais baixa (125 °C) com valores em torno de 0,8 g/100gads e diminui com a temperatura (175 °C): EB > OX > PX> MX. A selectividade é vista como muito baixa, mas pode mos dizer que quando a temperatura diminui
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
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