1,720,969 research outputs found
Application of esterified sago bark for removal of oil from palm oil mill effluent
Get PDFRemoval of emulsified oil in palm oil mill effluent (POME) is a challenge to palm oil industries. The aim of the present study was to develop a hydrophobic oil sorbent by incorporating fatty acid derivatives, namely stearic acid, on sago bark (SB) network via esterification process. The effect of esterification parameters such as the SB to stearic acid (SA) ratio (SB:SA), the amount of catalyst and the refluxing time on the oil removal efficiency of ESB and the optimization study were conducted via surface response methodology (RSM). The oil removal efficiency of SB and ESB in POME was also studied at different adsorption conditions in batch experiments. Artificial neural network (ANN) modelling was applied to model the column oil adsorption process. Chemical modification of SB has been successfully carried out via esterification with SA to afford ESB, the oil sorbent of high hydrophobicity and high oil removal efficiency. The esterification has successfully increased the hydrophobicity of SB by 42.2% and the oil removal efficiency in POME by 50.2%. The ESB produced at the optimum operating condition of SB:SA 1:1, 15% catalyst, and 8 h refluxing time gave the highest oil removal efficiency in POME (95.52%). The two most dominant influencing factors for ESB preparation were SB:SA and refluxing time. The batch oil adsorption study showed that the ESB exhibits better oil removal efficiency compared to SB in all studied conditions, namely adsorbent dosage, contact time, temperature and pH. Overall, the oil removal efficiency of both SB and ESB increased with increasing sorbent dosage and contact time. On the other hand, the oil removal efficiency of both SB and ESB decreased with the increasing temperature. Acidic pH was favorable pH condition for high oil removal efficiency. Overall, results showed a good correlation (R2 > 9.5) between experimental data and the intra-particle diffusion model for both SB and ESB. Results also showed that adsorption of oil in POME using SB was best described by Freundlich isotherm (R2=0.998), indicating heterolayer adsorption of oil on SB. The adsorption of oil in POME using ESB was better represented using Langmuir isotherm (R2=0.992), indicating a monolayer adsorption of oil onto the ESB surface. It is also evident from the study that ESB afforded good oil removal efficiency in deep bed filtration system. The ANN data showed that SB and ESB were found to remove oil from POME up to 59.12% and 89.79%, respectively in column system. The data means that after deep bed filtration of typical POME with initial oil concentration of 4000 mg/l using ESB, the treated POME is estimated to have 409 mg/l oil and grease content. ANN model was found to fit well with the experimental data with R2 > 0.95 for both training and testing data of SB and ESB. ANN study also indicated that all studied parameters are effective parameters in the sequence of temperature (30.09%) > pH (26.8%) > bed height (26.73% > flow rate (16.38%). The result revealed that the Thomas model and Yoon & Nelson model did not represented the experimental data very well. On the other hand, the column oil adsorption from POME using ESB can be excellently described by the intraparticle diffusion model. A multi-linearity plot of intra-particle diffusion model indicated the occurrence of three stages of adsorption during the experiment. Good oil removal efficiency and environmental friendliness make ESB a viable choice for use as bed material of a deep bed filter system for emulsified oil removal from POME. The importance of these research findings to advance the emulsified oil removal technology will hopefully find good use in the oil processing industry. The findings of this research will provide new insights to the emulsified oil removal technology
The Use of Microwave Derived Activated Carbon for Removal of Heavy Metal in Aqueous Solution
Get PDFPalm oil processing waste which is palm oil kernel shell (POKS) was converted to activated carbon (POKS AC) through 7 min microwave pyrolysis at temperature 270 °C followed by chemical activation using NaOH and HCl.
The adsorption study on Ni(II), Cu(II) and Cr(IV) was conducted to evaluate the efficiency of the prepared activated carbon to remove heavy metal. The adsorption capacity was determined as a function of adsorbate initial concentration and adsorbent dosage. Based on Langmuir isotherm, Ni(II) showed highest adsorption capacity of 40.98 mg/g, followed by Cr(IV) and
Cu(II) with adsorption capacity of 40.60 mg/g and 13.69 mg/g, respectively. Cr(IV) and Cu(II) showed better fitting to Freundlich isotherm model with high correlation regression indicating the applicability of heterogeneous adsorption. Ni(II) show better fitting with Langmuir isotherm that indicate monolayer coverage. The use of POKS AC is not only effective for adsorption
of Cr(IV), Ni(II) and Cu(II) in aqueous solution but also helps to overcome the over abundance of POKS waste problem
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
Empty Fruit Bunches Compost and Germination of Raphanus sativs L.
Get PDFOverabundance of empty fruit bunches (EFB) from palm oil industries has opened opportunity for its exploitationfor agricultural use as compost. In this study, palm oil EFB compost was prepared by the addition of wood chipsas a bulking agent and chicken manure to enhance the composting rate. Moisture was maintained at 50-70%during the 2-month composting. Results showed that the EFB compost containing high mineralisation indexcompared to the initial EFB samples after two months of the composting process. The important macronutrients;N, P, K, Ca and Mg and micronutrients Fe, Zn, Mn, Ni, Cu and B were found present in the EFB composts. Thefinal stage of EFB compost B showed high nutrient content with N, P, and K values of 2.21%, 3.65%, and 0.49%,respectively. Fe was the most outstanding element in the EFB compost as high as 9000 ppm. Germination resultsshowed that EFB compost with EFB:wood chips at 1:3 ratio exhibited better growth of leaves and root ofRaphanus sativs L. compared to 1:2 ratio. This indicated that the EFB compost is capable in improving soilfertility and growth of plants
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
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