1,720,954 research outputs found
Investigating Critical Mineral Recovery and Carbon Mineralization Potential in Coal Fly Ash
Get PDFCoal fly ash (CFA), a byproduct of coal combustion, represents an innovative opportunity to address the rising demand for critical minerals and the need to reduce CO2 emissions due to its significant concentrations of calcium and magnesium. By providing insights and preliminary data, this study aims to contribute to the foundational understanding necessary for future development.
A multidisciplinary approach was employed to assess CFA’s potential, including detailed chemical and mineralogical characterization using X-ray fluorescence (XRF), inductively coupled plasma mass spectrometry (ICP-MS), X-ray diffraction (XRD), and scanning electron microscopy (SEM). XRD analysis revealed crystalline phases in the CFA samples. At the same time, SEM imaging identified the characteristic morphology of coal fly ash, with particle sizes ranging from submicron to several micrometers. These analyses provided a comprehensive elemental and mineralogical profile for optimizing mineral recovery and carbonation processes.
Experimental tests involved roasting, precipitation, and leaching under acidic, basic, and aqueous conditions, followed by carbonation experiments. These investigations evaluated extraction efficiency, selectivity, and operational parameters quantified for critical minerals recovery and carbon capture capacity. HCl leaching outperformed other methods in terms of total REE (TREE) recovery (\u3e90%), followed by NaOH and water leaching at elevated temperatures (~40%) and NH4Cl (~30%). NaOH leaching demonstrated the best selectivity (low contamination), followed by NH4Cl, while HCl leaching showed poor selectivity. Water leaching with pre-treatment (roasting) improved selectivity for metals but not for TREE. Overall, HCl leaching at 1 M and 3 hours balanced high TREE recovery and operational practicality, making it the most suitable choice for subsequent carbonation tests. For carbonation, the best results were obtained using 5M NaOH and reaction at 50°C with CO2 pressure of 80 psi and an inlet flow rate of 1 L/min, achieving up to 60% recovery for TREE and calcium and selectivity of targeted pH of 4 and 7.
These findings underscore CFA\u27s potential to address environmental challenges associated with coal combustion residues while advancing circular economy principles by converting waste into valuable resources. By providing a robust foundational framework, this research marks a pivotal step toward harnessing CFA\u27s capabilities to tackle environmental and resource-related issues
Pengaruh Waktu Adsorbsi Dalam Proses Pemurnian Minyak Goreng Bekas Menggunakan Bioadsorben Tandan Kosong Kelapa Sawit
Get PDFMinyak goreng termasuk salah satu bahan pangan yang sangat dibutuhkan oleh masyarakat dalam kehidupan sehari-hari. Pemakaian minyak goreng secara terus menerus pada temperatur tinggi, menghasilkan minyak bekas yang tidak layak lagi digunakan, karena tidak baik bagi kesehatan tubuh. Agar minyak goreng bekas dapat dimanfaatkan kembali, maka perlu dilakukan pengolahan untuk meningkatkan kualitasnya. Pada penelitian ini dilakukan pemurnian minyak goreng bekas menggunakan bioadsorben dari Tandan Kosong Kelapa Sawit (TKKS). Penelitian dibagi menjadi dua tahap, tahap pertama adalah proses delignifikasi TKKS menggunakan NaOH sehingga dihasilkan bioadsorben. Tahap selanjutnya adalah proses adsorbsi terhadap minyak goreng bekas menggunakan bioadsorben. Proses adsorbsi dilakukan dengan variabel waktu, dari 30 menit sampai 150 menit. Hasil penelitian menunjukkan, setelah waktu adsorbsi 150 menit minyak goreng bekas mempunyai bilangan peroksida, angka asam, dan nilai absorbasi warna terkecil yaitu sebesar 24 mek H2O2/kg ; 0,2805 mg/g lemak ; dan 0,329 Abs. Sedangkan kadar FFA minyak goreng bekas terendah pada waktu adsorbsi 90 menit yaitu sebesar 0,1315%, penambahan waktu adsorbsi menjadi 120 menit dan 150 menit tidak menurunkan kadar FFA.
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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