1,721,180 research outputs found
Tiga pensyarah UPM dianugerahkan Malaysia’s Rising Star Award 2016
Full text linkPUTRAJAYA, 1 Nov – Tiga pensyarah Universiti Putra Malaysia (UPM), Prof. Dr. Jinap Selamat, Prof. Madya Dr. Lim Hong Ngee dan Prof. Dr. Mohd Rafii Yusof dianugerahkan Malaysia’s Rising Star Award (MRSA) oleh Menteri Pendidikan Tinggi, Dato’ Seri Idris Jusoh
Dua pensyarah UPM menang Anugerah Akademik Negara
Full text linkPUTRAJAYA, 3 Nov - Dua pensyarah Universiti Putra Malaysia (UPM), Dr. Mohd Yusof Saari dan Prof. Madya Dr. Lim Hong Ngee memenangi anugerah pada majlis Anugerah Akademik Negara (AAN) ke-10, malam in
Process intensification of 2-ethylhexyl caprylate/caprate synthesis via a pulsed loop reactor: Multi-objective optimization
Full text linkThis work proposes the optimization of 2-ethylhexyl (2-EH) caprylate/caprate synthesis in a pulsed loop reactor, and the energy efficiency of the reactor was assessed. 2-EH caprylate/caprate can be used as a biodegradable base fluid. Only 0.4 wt% catalyst concentration was used in the reaction. The face-centred central composite design (FCCD) experiment coupled response surface methodology (RSM) has been implemented to screen independent parameters. The optimization process showed that vacuum pressure was the most influential factor followed by oscillation speed, temperature and time. The maximum conversion of 98 % and yield of 89 % were achieved under optimal conditions of 78 °C, 10 mbar, 20 min and 155 rpm. Meanwhile, energy balance calculation indicated that the usage of low vacuum pressure not only significantly reduced the total heat duty from 1381 kJ (1 atm) to 823 kJ (10 mbar) but also alleviated the reaction temperature from 172 °C (1 atm) to 78 °C (10 mbar). The calculation also demonstrated that the reflux-stirred tank reactor produced a lower conversion and yield of ester yet 6 kJ higher total heat duty compared to the pulsed loop reactor, indicating a cost-saving with the pulsed loop reactor.
ROBIAH BINTI YUNUS// SITI ZULAIKA BINTI RAZALI, SURAYA BINTI ABDUL RASHID, LIM HONG NGEE
High Internal Phase Emulsion As A Reaction Medium For Fabrication Of Brushite Crystal
Full text linkThis present work was aimed at fabrication of porous brushite crystals using oil-in-water
high internal phase emulsion stabilized by synthesized palm-based nonionic surfactant
as a reaction medium. This research work was divided into four categories. The first part
of the work involved synthesizing palm-based nonionic surfactants. Palm oil derivatives,
lauryl, palmityl and stearyl alcohols as renewable resources, were ethoxylated with an
average of three, six (or eight or nine) and 100 moles of ethylene oxide. The critical
micelle concentration of the synthesized surfactants was found to decrease with
increasing ethylene oxide head groups due to intertwist amongst the head groups. This
phenomenon enhances surfactant-surfactant interaction rather than surfactant-solvent
interaction which increases the rate of micellization as proven by the Gibbs energy. The
increase in the surfactant tail length had minimal effect on micellization. The second
part of the work was to stabilize the high internal phase emulsion using the synthesized
surfactants. The oil phase was vegetable oil, namely olive and olein oils. These UPLOAD emulsions, with dispersed phase of more than 75 wt%, were easily prepared by one-pot
homogenization. Due to the high oil volume fraction, the oil droplets were no longer
spherical but were squeezed to take the shape of polyhedral. Light scattering results
showed that the droplet size increased with increasing ethylene oxide chain length. The
rheology of the emulsions was governed by droplet size and oil volume fraction. The
emulsions exhibited high stability as indicated by the rheological measurements even
after storage at 40oC for three months. The third part of the work was on the fabrication
of brushite crystals with high degree of porosity using the high internal phase emulsion
as a reaction medium. The porosity of the crystals was manifested by precursor
concentration, surfactant concentration, oil volume fraction, mixing method, mixing
time, aging temperature, precursor type, mode of recovery and surfactant head group.
Pore size of the brushite crystals was less than 5 μm. The mechanism for the formation
of porous brushite crystals was postulated schematically based on the small angle x-ray
scattering analysis. The fourth and final part of this work was related to the application
of the porous brushite crystals as drug delivery devices. Prior to the controlled release
study, the crystals were subjected to cytotoxicity test to ensure their compatibility with
synoviocytes, which are cells that line the knee joints of rabbits. The crystals were found
to enable cell growth for up to five days. Sodium ampicillin, a wide spectrum antibiotic,
was successfully loaded into the pores of the crystals and subsequently released in vitro
for 14 days. This work underlines the simplicity of using highly stable high internal
phase emulsion as a reaction medium for the fabrication of porous brushite crystals, in
which when loaded with drug, exhibited potential as localized bone treatment
demonstrated by the promising controlled release rate
Versatile water soluble graphene nanoplatelets for water-based polymers
No full textWater insoluble graphene nanoplatelets was converted to water soluble graphene nanoplatelets (GNPs) by a facile modification method. The water soluble GNPs easily dispersed in water-based polymers such as latex and polyvinyl alcohol with only mild agitation. The GNPs-fortified latex and GNPs-fortified polyvinyl alcohol (PVA) film yielded an average resistance of 1.8 x 104 Ω and 1.4 x 104 Ω, respectively. A mixture of water soluble GNPs and PVA was electrospun to produce a GNPs-fortified PVA nanofibre membrane. Subsequently, the nanofibre membrane was carbonized to produce a GNPs-fortified carbon nanofibre (CNF) membrane. The electrochemical performance of the GNPs-CNF membrane was measured. The current density of GNPs-CNF membrane increased by twofold, and the galvanostatic charge-discharge duration doublefold, as opposed to the neat CNF membrane. The GNPs-CNF membrane achieved an average stability of more than 95% for 1,000 cycles of galvanostatic charge-discharge
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
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