1,721,030 research outputs found
Effective uranium biosorption by macrofungus (Russula sanguinea) from aqueous solution: equilibrium, thermodynamic and kinetic studies
No full textRussula sanguinea (R. sanguninea) macrofungus was employed as a novel cost-effective biosorbent for efficient removal of U(VI) ions from aqueous solution. FT-IR spectroscopy and SEM/EDS technique were used for morphological and chemical characterizations. The maximum adsorption capacity of the macrofungus was found as 174.3 mg/g at pH 5 and 20 A degrees C. The kinetic data best fit with the pseudo-second-order kinetic model (r (2) > 0.99 for the studied temperatures). The exothermic and spontaneous nature of the biosorption process was confirmed by the thermodynamic findings. The reusability test demonstrated that the macrofungus had a good sorption/desorption performance.Unit of the Scientific Research Projects of Cumhuriyet University; Gaziosmanpasa University; Karadeniz Technical University; King Fahd University of Petroleum and Minerals; Turkish Academy of SciencesThe authors are fully grateful for the financial support of the Unit of the Scientific Research Projects of Cumhuriyet University, Gaziosmanpasa University, Karadeniz Technical University and King Fahd University of Petroleum and Minerals due to their some analysis feasibilities. Dr. Mustafa Tuzen also thanks to Turkish Academy of Sciences for financial support
Equilibrium, thermodynamic and kinetic investigations for biosorption of uranium with green algae ( Cladophora hutchinsiae )
No full textRemoval of toxic chemicals from environmental samples with low-cost methods and materials are very useful approach for especially large-scale applications. Green algae are highly abundant biomaterials which are employed as useful biosorbents in many studies. In the present study, an interesting type of green algae, Cladophora hutchinsiae (C. hutchinsiae) was used for removal of highly toxic chemical such as uranium. The pH, biosorbent concentration, contact time and temperature were optimized as 5.0, 12 g/L, 60 min and 20 degrees C, respectively. For the equilibrium calculations, three well known isotherm models (Langmuir, Freundlich and Dubinin-Radushkevich) were employed. The maximum biosorption capacity of the biosorbent was calculated as about 152 mg/g under the optimum batch conditions. The mean energy of biosorption was calculated as 8.39 kJ/mol from the D-R biosorption isotherm. The thermodynamic and kinetic characteristics of biosorption were also investigated to explain the nature of the process. The kinetic data best fits the pseudo-second-order kinetic model with a regression coefficient of > 0.99 for all studied temperatures. The calculated Delta H degrees and Delta G degrees values showed that the biosorption process is exothermic and spontaneous for temperatures between 293 and 333 K. Furthermore, after seven cycling process, the sorption and desorption efficiencies of the biosorbent were found to be 70, and 58%, respectively meaning that the biosorbent had sufficiently high reusability performance as a cleanup tool. (C) 2017 Elsevier Ltd. All rights reserved.Cumhuriyet University; Gaziosmanpasa University; Karadeniz Technical University; Turkish Academy of SciencesThe authors are fully grateful for the financial support of the Unit of the Scientific Research Projects of Cumhuriyet University, Gaziosmanpasa University and Karadeniz Technical University. Dr. Mustafa Tuzen also thanks to Turkish Academy of Sciences for financial support
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
Optimization of a rapid and sensitive ultrasound-assisted liquid-liquid microextraction using switchable hydrophilicity solvent for extraction of β-carotene in fruit juices and vegetables
No full textA simple, rapid and sensitive ultrasound-assisted liquid-liquid microextraction by switchable hydrophilicity solvent (UA-LLME-SHS) method was developed first time for extraction and determination of beta-carotene from fruit juices and vegetables using a spectrophotometer. The effect of pH, solvent dose, ultrasound time, volume of NH4OH, volume of NaCl (w/v) and effects of different chemicals on extraction recovery was investigated. The proposed method showed good extraction recovery of beta-carotene. The working range of the developed method was 50-700 ng mL(-1). Limits of detection and quantification were 15.5 mu g L(-1 )and 50 mu g L-1, respectively. The intraday and interday precisions of the developed method was investigated for 75 ng mL(-1) and 400 ng mL(-1) of p-carotene. As a result of the study, the relative standard deviation values were in the range of 2.8-3.3 % and 3.0-4.2 % for the intraday and interday studies, respectively. The enhancement factor was 114 and extraction recovery of beta-carotene was found 98.3 %. The factorial design was drawn to know the combined effects of variables and their significant and insignificant effects on the determination of the beta-carotene.Turkish Academy of Sciences (TUBA), Turkey; Turkey BursaryMuhammad Farooque Lanjwani thanks to Turkey Bursary for his financial supports. Dr. Mustafa Tuzen also thanks to Turkish Academy of Sciences (TUBA), Turkey for partial supports
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
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