1,720,954 research outputs found
PDMS-coated porous PVDF hollow fiber membranes for efficient recovery of dissolved biomethane from anaerobic effluents
No full textThis report demonstrates the fabrication of a composite hollow fiber membrane that efficiently recovers dissolved methane (dCH4) from anaerobic wastewater treatment effluents via membrane contactor (MC) process. We first fabricated highly porous hollow fiber membranes (∼85% porosity) using polyvinylidene difluoride (PVDF). Then, we coated the whole structure (bulk), or lumen side of PVDF supports with polydimethylsiloxane (PDMS), a hydrophobic polymer possessing high gas permeability. The adjustment of the concentration of PDMS precursor mix could effectively serve for tuning the performance characteristics of MC membranes and helped suppress membrane wetting, a major performance-reducing factor. Despite their denser skin layers, the lumen-modified membranes demonstrated superior dCH4 recovery flux. Mass transfer analyses have confirmed the importance of preserving bulk porosity while coating the membrane surfaces. The long-term performance tests performed using actual anaerobic effluents suggested that the PDMS coating did not accelerate fouling, such that the lumen-modified MC membranes showed an almost steady flux for 8 days with an anaerobic membrane bioreactor effluent. A high-strength effluent, obtained from an up-flow anaerobic sludge blanket reactor, induced faster fouling. However, we observed only a ∼20% flux decline in a 10-day operation. Thus, we propose that the designed PDMS-PVDF composite membranes are promising for industrial practices.National Research Foundation (NRF)Accepted versionThis study was supported by the research grant provided by the Singapore National Research Foundation under its Environmental & Water Research Program (Project Ref No:1301-IRIS-49) and administered by PUB, Singapore's national water agency. We would like to acknowledge Mr. Chong Yang Chuah for particle size measurements. We also thank the developers of the free ware (or limited freeware) graphic software platforms (Lucidchart, Inkscape, ImageBot) used for the preparation of illustrations in this study
Incorporation of CoIII acetylacetonate and SNW-1 nanoparticles to tailor O2/N2 separation performance of mixed-matrix membrane
No full textMixed-matrix membranes containing a porous organic framework (SNW-1 nanoparticles) and a cobalt-based complex (Co(acac)3) were fabricated using the solution-casting technique for potential applications in O2/N2 separation. The mixed-matrix membranes did not show any appreciable defects. In the following mixture gas permeation testing conducted with a binary mixture composed of 21% O2 and 79% N2 at 1 bar feed pressure and 35 °C, the mixed-matrix membranes containing SNW-1 nanoparticles showed an enhanced O2 permeability, whereas Co(acac)3 improved the O2/N2 selectivity. Hence, with a combination of both nanoparticles and a Cobalt complex in a polymer matrix, a clear synergistic enhancement in O2/N2 separation properties was reported, in which O2 permeability and O2/N2 selectivity were escalated by 33% and 18%, respectively. Solubility-diffusivity analysis in the mixed-matrix membranes revealed that SNW-1 and Co(acac)3 can improve O2 diffusivity and O2 solubility, respectively, resulting in an enhancement of both O2 permeability and O2/N2 selectivity for membranes containing both the nanoparticles and the cobalt complex. Future efforts will be focused on developing asymmetric hollow fiber membranes with thin skin layer comprising both SNW-1 and Co(acac)3.Ministry of the Environment and Water ResourcesNational Environmental Agency (NEA)National Research Foundation (NRF)Accepted versionThis research is supported by the National Research Foundation, Prime Minister's Office, Singapore, and the National Environment Agency, Ministry of the Environment and Water Resources, Singapore, under the Waste-to-Energy Competitive Research Programme (WTE CRP 1601 105)
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
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
- …
