1,721,065 research outputs found
Development of solid acid catalysts for biodiesel production from high free fatty acid feedstock / Yahaya Muhammad Sani
Full text linkNumerous energy crises have been confronting the world due to excessive utilization of
the world's depleting oil reserves by the ever-increasing human population. Concerns
such as deteriorating health standards and environmental degradations have led to the
search for sustainable biofuel alternatives. However, the recent nose-diving of the Brent
crude oil price makes the search for sustainable catalysts more arduous. Consequently,
the present study investigated two distinct catalytic routes for producing biodiesel from a
cheap feedstock, which could have competitive edge with fossil diesel. Firstly, the study
explored the potentials of converting wastes from oil palm biomass such as empty fruit
bunch (EFB), palm frond (PTF), spikelet (PTS) and waste fruit (WPF) into sulfonated
mesoporous solid acids via carbonization-sulfonation method. Brunauer-Emmet-Teller
(BET), powder X-ray diffraction (XRD), Energy dispersive X-ray (EDX), and field
emission scanning emission microscopy (FE-SEM) analyses elucidated the structural and
textural properties of the catalysts. Further, Fourier transform-infrared (FT-IR)
spectroscopy and titrimetric analyses measured the strong acid value and acidity
distribution of the materials. These evidenced large mesopore volumes, large surface
areas, uniform pore sizes, and high acid densities on the catalysts. The catalytic activity
exhibited in esterifying used frying oil (UFO) containing high (48%) free fatty acid (FFA)
further confirmed these properties. Interestingly, sEFB/300 and sPTS/400 converted
more than 98% FFA into fatty acid methyl esters (FAMEs). This is outstanding
considering the lower reaction parameters of 3 h, 5:1 methanol-to-oil ratio, and moderate
temperature range between 100 and 200 °C.
Equally, the study delved into a process considered to have attained state-of-the art status;
sulfated zirconia (SZ), which has been the subject of numerous reports since its discovery
in 1979. The catalytic activity of SZ in esterifying FFA and transesterifying triglycerides
iv
(TG) simultaneously from high-FFA containing feedstocks into biodiesel has led to
claims that SZ are superacids, or at least very strong acids. However, SZ has some
inherent limitations such as slow reaction rates. Similarly, despite the numerous
advantages of zeolite catalysts, microporosity hinders their industrial applicability for
biodiesel production. Evidently, several reports on optimal preparative conditions that
produced superacidic materials abound via carefully controlled procedures. Nonetheless,
to date, no study has reported the effect of grafting zeolite on SZ for biodiesel production.
Further, there is no information from open literature regarding biodiesel production over
SZ doped with ytterbium, Yb. Consequently, this study investigated the prospects of
combining mesoporous zeolite and SZ; and effect of doping SZ with Yb for biodiesel
production. The study synthesized different composite catalysts that have potential to
maximize activity and minimize adsorbate-induced surface reconstruction, with
consequent reduction in net energy consumption. Remarkably, large mesoporosity, high
amount, and dispersion of active sites on Yb-doped SZ ensured significant activity despite
low specific surface area that was due to short aging period. However, different sulfation
methods showed marginal effect on SZ. Interestingly, the catalyst achieved more than
99% conversion under moderate conditions. These findings will definitely help to further
the biofuel central policy of replacing petrodiesel in the possible near future
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
Net pancake maker / Muhammad Fakhrun Amin Yahaya, Muhammad Firdaus Amin Mohd Zainee and Nur Syuhada Mohd Yusof
Full text linkNet Pancake Maker is high voltage device. The main function of this device is to make the net pancake automatically. To be specific, when the device started with ON the power supply and the temperature sensor start operating. The temperature sensor will detect the temperature of pan. The automatic valve were set to 2 minutes before the valve open to release the net pancake batter. Shape the pancake with our own creativity manually. The valve will close after it reach the end of the time
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
- …
