1,720,961 research outputs found
Techno-economic Analysis of a Lignocellulosic Biorefinery Producing Microbial Oils by Oleaginous Yeasts
No full textThe lignocellulosic biomass valorisation is a central challenge of the bioeconomy transition, which passes through optimization of the entire value chain, from feedstock availability, sustainable conversion processes, to final target products. In this framework, the oleaginous yeasts represent a versatile tool to produce biobased chemicals and intermediates. They are flexible microbial factories able to grow on different side-stream carbon sources such as those deriving from lignocellulosic biomass, and this characteristic makes them excellent candidates for integrated biorefinery processes through the production of microbial lipids/oils. This work aims at a techno-economic analysis of a lignocellulosic biorefinery producing microbial oils by oleaginous yeasts (Lipomyces tetrasporus). The wheat straw residues were considered as the lignocellulosic feedstock thanks to a huge amount in the European territory. Experimental data obtained by a complete lab-scale 2G-sugars platform (steam explosion pretreatment, enzymatic hydrolysis, fermentation) were used for the analysis until microbic growth. Commercial/literature data were considered for the lipids extraction and purification stages. An assessment of the mass and energy balances, equipment sizing, costs estimation was carried out with the main results showing a production cost of the microbial oil about 4 €/kg with the enzymes supply as the major cost contribution
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
Catalytic and biocatalytic cascade conversion of giant reed and cardoon residues to glucose, levulinic acid, and long-chain fatty acid methyl esters
No full textGiant reed was hydrolysed by the green salt FeCl3 under microwave irradiation. Differently, cardoon residues were pretreated by steam explosion and hydrolysed by the same catalyst. Each pretreatment showed efficient biomass fractionation, with xylan hydrolysis reaching 99 mol% for giant reed and 70 mol% for cardoon. Then, glucose yields of 55 and 30 mol% were obtained for giant reed and cardoon, respectively, under mild reaction conditions (34 min, 150 °C, biomass loading 9 wt%, FeCl3 2.7 wt%). Sugars-rich hydrolysates were fermented by the yeasts L. starkeyi and L. tetrasporus to produce triglycerides. L. starkeyi achieved a lipid yield of 13.5 wt% from giant reed hydrolysate and 14.2 wt% from cardoon hydrolysate. L. tetrasporus reached a lipid yield of 16.0 and 17.6 wt% from giant reed and cardoon hydrolysate, respectively. Moreover, both yeasts were able to convert cardoon hemicellulose into triglycerides, reaching at pH 5.5 a lipid yield of 13.9 wt% (L. starkeyi) and 19.4 wt% (L. tetrasporus). These oils were converted to long-chain fatty acids methyl esters. The final valorisation of unconverted glucan in solid residues resulted in the FeCl3-catalysed production of levulinic acid and formic acid to close the biorefinery cycle of both biomasses
Inhibitors derived from wheat straw hydrolysate can affect the production of succinic acid by Actinobacillus succinogenes
No full textLignocellulosic biomasses are promising source of fermentative sugars for the production of succinic acid. The lignocellulosic matrix must be pretreated to make the sugars available for the fermentation, but the most tested operative conditions can generate inhibitors as acetic acid, furans, phenolic compounds. Inhibitors remained an obstacle for the implementation of succinic acid production starting from recalcitrant biomasses as wheat straw. Batch tests were performed at two starting concentrations of strain, sugars (glucose, glucose and xylose) and inhibitors (acetic acid and furfural) by comparing the fermentation in standard broth medium and hydrolysate. Notwithstanding the presence of acetic acid (52.5 mg/L) and furfural (15 mg/L), succinic acid was obtained at 9*10−2 ± 7*10−3 g/L by starting from wheat straw hydrolysate that contained glucose (1.1 g/L), xylose (0.4 g/L) and without additional nitrogen source. Therefore, the study highlighted that a more concentrated inoculum was able to reduce the synergistic effect of inhibitors at their highest concentrations. The results obtained may contribute to improve succinic acid production from the biomasses that have been under-exploited but abundantly available, as wheat straw, for which solutions must be found to solve the problem of inhibitors production or to mitigate its effect on the fermentation process
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
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