1,720,960 research outputs found
Potential application of membrane capacitive deionisation for bromide removal in seawater desalination
Get PDFUniversity of Technology Sydney. Faculty of Engineering and Information Technology.The freshwater shortage is becoming an increasingly scarce resource due to rapid population growth and increased freshwater demand for industrial activities. The situation is further getting worse due to the effect of climate change as evident from extreme events such as droughts. In order to secure freshwater availability, most countries, including Australia are resorting to seawater desalination because seawater provides a reliable and climate-independent water source. Among desalination technologies, seawater reverse osmosis (SWRO) is the dominant technology due to its better energy efficiency and also its high salt rejection rates. While single-stage SWRO is adequate for the production of high-quality drinking water in most countries, in Australia, due to the strict requirement for bromide removal to prevent the formation of toxic bromide related disinfection by-products in the water, additional stage such as 2nd pass brackish water reverse osmosis (BWRO) has to be used. As a result, all the SWRO plants are designed as two-stage SWRO, which adds significant cost to the overall SWRO plant.
Recently, capacitive deionisation (CDI) has emerged as a suitable alternative for desalination of low-saline water sources compared with membrane processes. CDI is an electrosorption process where ions are removed by the charged carbon electrodes. Some of the advantages of CDI technology are low energy consumption, removal of all types of charged ions such as bromide and its ability to effectively desalinate water at a very low voltage (1 V) application. Therefore, in this research, the application potential of membrane CDI, which is an advanced version of CDI, is investigated for bromide removal. A detailed assessment of bromide removal efficiency and energy consumption were compared with that of conventional 2nd pass BWRO.
Several investigations related to bromide removal in MCDI were evaluated both at lab-scale and pilot-scale studies. The fundamental studies using lab-scale showed that bromide could be effectively removed using a commercially available carbon electrode. Further, a pilot-scale MCDI demonstrated that MCDI can be operated at high water recovery using variable flow rates during the adsorption and desorption stages. It was also found that using a much lower flow rate during desorption compared to adsorption stage can produce an acceptable water quality with high water recovery. The energy consumption of lab-scale and pilot-scale studies were between 0.11-0.16 kWh/m³ of treated water, which is only about 30-45% of the energy consumed by the 2nd pass BWRO in Perth desalination plant.
A fundamental lab-scale study on the selectivity between bromide and iodide, which is another important inorganic halide for the formation of toxic disinfection by-products was also conducted. The results showed that iodide was more selectively removed over bromide even in the presence of significant background concentration of sodium chloride mainly due to the high partial-charge transfer coefficient of iodide compared to bromide ions although both these ions have similar ionic charge and hydrated radius. The result also showed that MCDI could be a potential alternative for the removal of both bromide and iodide during water treatment.
One of the major disadvantages of capacitive deionisation-based desalination is the inability of the electrodes to selectively remove the target ions from a mixture of other background ions. Although bromide can be effectively removed in MCDI, especially in low salinity water, its removal efficiency can be reduced if the total salt content in the feed water is high. Therefore, a bromide selective composite electrode was developed by coating a slurry of grounded bromide selective resin and anion exchange polymer on the surface of the commercial carbon electrode. The composite electrode demonstrated high selectivity for the bromide, which was 3.4 times that of conventional MCDI. A further test on bromide selectivity in a complex mixture of several anions showed that bromide removal was 10 times that of conventional MCDI. The incorporation of bromide selective resin enhanced the capture and transport of bromide ions onto the carbon electrode while impeding the transport of other competing ions. The use of bromide selective electrodes in MCDI is expected to further reduce energy consumption while improving bromide removal efficiency
BHUTAN'S MACROECONOMIC SIMULATION ANALYSIS : An application of an Overlapping generations model
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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
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