1,720,982 research outputs found
Enhanced lignocellulosic component removal and biomethane potential from chestnut shell by a combined hydrothermal–alkaline pretreatment
No full textThis study proposes new perspectives for the management and biorefinery of wastes deriving from the agri–food sector such as chestnut shell (CS), which was here used as an organic feedstock for biomethane production through anaerobic digestion (AD). 1–5% alkaline (i.e. NaOH and KOH), hydrothermal (i.e. at 100 °C) and combined hydrothermal–alkaline pretreatments were employed to enhance the CS biodegradability prior to biochemical methane potential (BMP) tests conducted under mesophilic conditions. The hydrothermally–pretreated CS with 3% NaOH achieved the highest biomethane yield of 253 (±9) mL CH4·g VS−1 coupled to a volatile solid reduction of 48%. The hydrothermal–alkaline pretreatment positively affected both delignification and hemicellulose polymerization, promoting an approximately 2.4–fold higher substrate biodegradability compared to the untreated CS, which only reached a CH4 production of 104 (±5) mL CH4·g VS−1. AD proceeded via volatile fatty acid accumulation, subsequently followed by methane production that was effectively simulated via the modified Gompertz kinetic having a R2 of 0.974–0.999. Among the physical–chemical parameters characterizing the CS, the soluble chemical oxygen demand (sCOD) was highly correlated with the BMP showing a Pearson coefficient of 0.952. The cumulative biomethane yield, the sCOD and the cellulose, hemicellulose and lignin amount of CS were also processed through the least square method, obtaining a useful regression equation to predict the BMP. The economic assessment indicated that the hydrothermal–alkaline pretreatment is a cost–effective method to improve the BMP of CS, also for future full–scale applications
Combined ultrasonic–hydrothermal pretreatment to improve the biomethane potential of hazelnut shell
No full textThis work evaluated for the first time the employment of hydrothermal alone (i.e. at 60, 80 and 100 °C) and combined ultrasonic–hydrothermal pretreatments on hazelnut shell (HS) to promote the energetic valorization of HS through anaerobic digestion. The highest cumulative biomethane yield of 137 mL CH4·g VS−1 was achieved performing biochemical methane potential tests under wet–mesophilic conditions with the hydrothermally (i.e. at 100 °C) and ultrasonically–pretreated HS. This CH4 yield was 2.3–fold higher than that obtained with the raw HS due to an enhanced hemicellulose polymerization and delignification after the sequential hydrothermal and ultrasonic pretreatment. Under the same pretreatment conditions, total volatile fatty acids peaked at 755 mg HAc L−1. The biomethane production followed the modified Gompertz model (R2 = 0.993–0.996) and a Pearson correlation test showed that it was mainly influenced by the soluble chemical oxygen demand (i.e. 0.983). A positive energy balance revealed that the produced biomethane can offset the energy needed for the pretreatment
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
- …
