1,720,957 research outputs found
New catalysts and activity tests for synthesis gas from dry reforming of methane reaction
No full textÇalışmada, metanın kuru reformlanma reaksiyonuyla sentez gazı eldesi için yeni, aktif ve kok oluşumuna karşı dirençli katalizörlerin geliştirilmesi amaçlanmıştır. Bu amaçla, zirkonyum dioksit veya titanyum dioksit destekli Ni ve/veya Co içerikli katalizörler sentezlenmiştir. Zirkonyum dioksit destek malzemeleri NH3 (ZrO2), P123 (ZrO2-P) ve CTMABr (ZrO2-C) kullanılarak farklı hidrotermal yöntem reçeteleri ile sentezlenmişlerdir. Malzemelerin yüksek yüzey alanına ve uniform gözenek boyutu dağılımına sahip olduğu N2 adsorpsiyon-desorpsiyon analiziyle belirlenmiştir. Zirkonyum dioksit destekli Ni ve/veya Co katalizörler emdirme yöntemi, "one-pot" ve birikme-çökelme yöntemleri ile sentezlenmiştir. Bazı katalizörler, farklı reaksiyon sıcaklıklarında (600 ve 800 0C) ve alıkonma sürelerinde (0,1-0,5 s.g.cm-3) metanın kuru reformlanma reaksiyonunda test edilmişlerdir. 600 0C'de 5Ni-ZrO2-P katalizörü ile 0,4 s.g.cm-3 alıkonma süresinde gerçekleştirilen 4 saatlik reaksiyon sonucunda yüksek CH4 (% 27) ve CO2 (% 39) dönüşümü elde edilmiştir ve katalizör yapısında karbon birikiminin olmadığı belirlenmiştir. Bu nedenle, endotermik olan metanın kuru reformlanma reaksiyonu daha yüksek sıcaklıkta (800 0C) 5Ni-ZrO2-P katalizörü ile tekrarlanmıştır. Reaksiyon sonrasında (4 saat) % 88 CH4 ve % 88 CO2 dönüşümü elde edilmiştir ve karbon oluşmadığı belirlenmiştir. Aynı katalizörün, 800 0C sıcaklıkta gerçekleştirilen 50 saatlik reaksiyon süresi boyunca kararlı davranış gösterdiği ve kok oluşumuna karşı dirençli olduğu gözlemlenmiştir. Çalışma kapsamında, CTMABr ile hazırlanan ZrO2-C destekli farklı oranlarda Ni ve Co içeren katalizörler ile de katalitik aktivite testleri yürütülmüştür. Farklı oranlarda Ni ve Co içeren katalizörler içerisinde en yüksek CH4 (% 31) ve CO2 (% 36) dönüşümü 12Ni@ZrO2-C-T3-1 (% 12 Ni) katalizörü ile elde edilmiştir. Ancak bu katalizörün kok oluşumuna karşı dirençsiz olduğu TG ve XRD analizleri ile belirlenmiştir. 5Co@ZrO2-C-T3-1 (% 5 Co) katalizörünün nispeten daha düşük aktiviteye sahip olduğu ancak kok oluşumuna karşı dirençli olduğu gözlemlenmiştir. Çalışmanın devamında, titanyum dioksit destek malzemeleri, Kartini (TiO2-KC), EISA (TiO2-EP), hidrotermal (TiO2-HP) ve sol-jel yöntemleri (TiO2-SG3) ile hazırlanmışlardır. Titanyum dioksit destekli Ni katalizörleri %5 Ni içerecek şekilde emdirme yöntemi ile hazırlanmıştır. Titanyum dioksit destekli katalizörler içerisinde en yüksek CO2 (% 17) dönüşümüne 12Ni@TiO2-SG3-1 katalizörü ile ulaşılmıştır. Çalışmanın sonucunda, zirkonyum dioksit destek malzemesi kullanılarak sentezlenen katalizörlerin metanın kuru reformlanma reaksiyonunda daha yüksek aktivite gösterdikleri belirlenmiştir. Çalışma kapsamında hazırlanan 5Ni-ZrO2-P katalizörünün metanın kuru reformlanma reaksiyonu için aktif bir katalizör olduğu ve kok oluşumuna karşı dirençli olduğu belirlenmiştir. Çalışma sonucunda, zirkonyum dioksit destekli katalizörlerin daha yüksek aktiviteye sahip oldukları belirlenmiştir.The aim of this study is to develop new, active and resistant to coke formation catalysts by dry reforming of methane reaction to produce syngas. For this purpose, zirconia or titania supported Ni and/or Co catalysts were synthesized. By using NH3 (ZrO2), P123 (ZrO2-P) and CTMABr (ZrO2-C), zirconia supported materials were synthesized by different hydrothermal methods. N2 adsorption-desorption isotherm of zirconia materials showed that these materials have high surface area and uniform pore size distribution. Zirconia supported Ni and/or Co catalysts were synthesized by impregnation, one-pot and deposition-precipitation methods. Dry reforming of methane was carried out fixed bed reactor system. Some of the catalysts were tested in dry reforming of methane at different reaction temperatures (600-800 0C) and space times (0.1-0.5 s.g.cm-3). High CH4 (27 %) and CO2 (39 %) conversions were obtained with 5Ni-ZrO2-P catalysts at 600 0C and 0.4 s.g.cm-3 for 4 hours reaction period and observed no coke formation. Therefore, dry reforming of methane was repeated with 5Ni-ZrO2-P at higher temperature (800 0C) due to endothermic reaction. After the reaction (4h), 5Ni-ZrO2-P was observed 88 % CH4 and 88 % CO2 conversions and found to be resistance to coke formation. Stable activity and coke resistance were observed by using the same catalysts during the long term activity tests at 800 0C for 50 hours. In this study, catalytic activity tests were also carried out with different amount of Ni catalysts supported by ZrO2-C and Co based catalysts. 12Ni@ZrO2-C-T3-1 (12 % Ni) had the highest CH4 (31 %) and CO2 (36 %) conversions among different amount of Ni and Co containing catalysts. However, after reaction 66 % coke formation is determined by TGA and XRD analysis. Relatively low activity was obtained with 5Co@ZrO2-C-T3-1 (5 % Co) catalyst and no coke formation was observed. In the continuation of this study, titania support metarials were prepared by Kartini (TiO2-KC), EISA (TiO2-EP), hydrothermal (TiO2-HP) and sol-gel methods (TiO2-SG3). Titania supported Ni catalysts were prepared by impregnation. Highest CO2 conversion (17 %) was provided by 12Ni@TiO2-SG3-1 catalyst among the titania supported catalysts. As a result of this study, it was determined that catalysts which were prepared by using zirconia supported had higher activity. 5Ni-ZrO2-P catalyst prepared in this study was determined as an active catalyst for dry reforming of methane reaction and also was found to be resistant to coke formation. At the end of this study, higher catalytic activity was obtained with zirconia supported catalysts
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
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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