1,720,964 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
Lignocellulosic Ethanol Production Based on Steam Pretreatment and SSF: Process Development through Experiments and Simulations
No full textLignocellulosic materials, such as wood, waste products from the forestry industry, agricultural residues and herbaceous crops, serve as an abundant and comparatively cheap feedstock with the potential to be used for large-scale ethanol production. However, the complex structure of lignocellulosic materials, the presence of various hexose and pentose sugars in hemicellulose, and the presence of various compounds that inhibit the fermenting organism constitute physical barriers that add to the production cost and make full-scale introduction economically more risky. The work presented in this thesis was aimed at improving the economics of lignocellulosic ethanol production, by investigating more cost-efficient ways to convert the carbohydrates to ethanol. Steam pretreatment of Salix was extensively assessed. Glucose yields of above 90% and xylose yields higher than 80% of the theoretical were obtained after enzymatic hydrolysis. Simultaneous saccharification and fermentation (SSF) of steam-pretreated Salix using baker’s yeast (S. cerevisiae) resulted in ethanol yields of above 80% of the theoretical, based on the glucan and mannan content of the raw material. Cultivating the yeast on part of the pretreatment liquid resulted in a more tolerant yeast, which made it possible to perform SSF with higher substrate loadings. The highest ethanol concentration obtained was 32.6 g/L. There is, however, room for further improvements, as discussed in this thesis. Process simulations were performed utilizing a model including all major process steps, which was implemented in the commercial flow-sheeting program Aspen Plus. The model input was based on experimental data recently obtained on lab scale or in a process development unit. An economic evaluation, including estimations of the ethanol production cost for different process configurations, was carried out based on the simulation results. The results clearly demonstrate the importance of a high ethanol yield and the necessity of utilizing the pentose fraction for ethanol production to reduce the production cost, especially when using a pentose-rich feedstock. A less energy-demanding process reduces the capital cost and results in higher co-product revenue, which is beneficial for the overall process economics. Although ethanol was shown to be the main product, i.e. yielding the major part of the income, the co-product revenue has considerable impact on the process economics, and the importance of good utilization of the entire feedstock was clearly shown. Utilization of the excess solid residue for heat and power production was highly favourable from the economic aspect. A spruce-based ethanol plant with such a configuration was shown to be competitive with, and in many ways more advantageous than, a biomass-based heat and power plant in terms of overall economics
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
Lignocellulosic Ethanol Production Based on Steam Pretreatment and SSF: Process Development through Experiments and Simulations
No full textLignocellulosic materials, such as wood, waste products from the forestry industry, agricultural residues and herbaceous crops, serve as an abundant and comparatively cheap feedstock with the potential to be used for large-scale ethanol production. However, the complex structure of lignocellulosic materials, the presence of various hexose and pentose sugars in hemicellulose, and the presence of various compounds that inhibit the fermenting organism constitute physical barriers that add to the production cost and make full-scale introduction economically more risky. The work presented in this thesis was aimed at improving the economics of lignocellulosic ethanol production, by investigating more cost-efficient ways to convert the carbohydrates to ethanol. Steam pretreatment of Salix was extensively assessed. Glucose yields of above 90% and xylose yields higher than 80% of the theoretical were obtained after enzymatic hydrolysis. Simultaneous saccharification and fermentation (SSF) of steam-pretreated Salix using baker’s yeast (S. cerevisiae) resulted in ethanol yields of above 80% of the theoretical, based on the glucan and mannan content of the raw material. Cultivating the yeast on part of the pretreatment liquid resulted in a more tolerant yeast, which made it possible to perform SSF with higher substrate loadings. The highest ethanol concentration obtained was 32.6 g/L. There is, however, room for further improvements, as discussed in this thesis. Process simulations were performed utilizing a model including all major process steps, which was implemented in the commercial flow-sheeting program Aspen Plus. The model input was based on experimental data recently obtained on lab scale or in a process development unit. An economic evaluation, including estimations of the ethanol production cost for different process configurations, was carried out based on the simulation results. The results clearly demonstrate the importance of a high ethanol yield and the necessity of utilizing the pentose fraction for ethanol production to reduce the production cost, especially when using a pentose-rich feedstock. A less energy-demanding process reduces the capital cost and results in higher co-product revenue, which is beneficial for the overall process economics. Although ethanol was shown to be the main product, i.e. yielding the major part of the income, the co-product revenue has considerable impact on the process economics, and the importance of good utilization of the entire feedstock was clearly shown. Utilization of the excess solid residue for heat and power production was highly favourable from the economic aspect. A spruce-based ethanol plant with such a configuration was shown to be competitive with, and in many ways more advantageous than, a biomass-based heat and power plant in terms of overall economics
Integration Options for High Energy Efficiency and Improved Economics in a Wood-to-Ethanol Process
Full text linkBackground: There is currently a steady increase in the use of wood-based fuels for heat and power production in Sweden. A major proportion of these fuels could serve as feedstock for ethanol production. In this study various options for the utilization of the solid residue formed during ethanol production from spruce, such as the production of pellets, electricity and heat for district heating, were compared in terms of overall energy efficiency and production cost. The effects of changes in the process performance, such as variations in the ethanol yield and/or the energy demand, were also studied. The process was based on SO2-catalysed steam pretreatment, which was followed by simultaneous saccharification and fermentation. A model including all the major process steps was implemented in the commercial flow-sheeting program Aspen Plus, the model input was based on data recently obtained on lab scale or in a process development unit. Results: For the five base case scenarios presented in the paper the overall energy efficiency ranged from 53 to 92%, based on the lower heating values, and a minimum ethanol selling price from 3.87 to 4.73 Swedish kronor per litre (0.41–0.50 EUR/L); however, ethanol production was performed in essentially the same way in each base case scenario. (Highly realistic) improvements in the ethanol yield and reductions in the energy demand resulted in significantly lower production costs for all scenarios. Conclusion: Although ethanol was shown to be the main product, i.e. yielding the major part of the income, the co-product revenue had a considerable effect on the process economics and the importance of good utilization of the entire feedstock was clearly shown. With the assumed prices of the co-products, utilization of the excess solid residue for heat and power production was highly economically favourable. The study also showed that improvements in the ethanol yield and reductions in the energy demand resulted in significant production cost reductions almost independently of each other
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