1,720,999 research outputs found
Electrokinetic-assisted filtration for fast and highly efficient removal of microplastics from water
No full textAmong engineered degradation and separation methods for microplastics (MPs) removal from aquatic environments, membrane filtration (MF) relying on a size exclusion mechanism has shown potential for effective treatment of various-sized MPs ranging from submicron to a few millimeters. However, basic concerns about MF involved in an inherent efficiency-flux trade-off and membrane fouling raise questions about its practical applicability. Here, an electrokinetic-assisted filtration fulfilled by introducing electrokinetic assistance into physical filtration is proposed as a new candidate able to address the concerns of MF. Our hybrid filtration system demonstrates outstanding filtration performance for tiny plastic specks (a removal efficiency of > 99.9 % and a flux of similar to 10,000 L m(2) h(-1)) only with a coarse physical filter, by electrokinetically arresting MPs passing through a filter lattice. In particular, consistent filtration performance is accomplished in our system regardless of MPs' types, sizes, concentrations, and chemical compositions due to the electrokinetic assistance solely depending on MPs' electrophoretic mobility. This study provides key insights into a highly scalable electrokinetic system, offering a practical solution to successfully deal with MPs pollution prevalent in aquatic environments.11Nsciescopu
Continuous ion separation via electrokinetic-driven ion migration path differentiation: practical application to lithium extraction from brines
No full textThe effective separation of Mg2+ from Li+ is the key for realizing efficient and economic lithium extraction from brine, but remains challenging due to their similar chemical properties. Recent approaches have enabled simultaneous magnesium removal and lithium extraction from high Mg2+/Li+ ratio brines, but their reliance on physical or chemical filters has led to inconsistent performance dependent on brine conditions and corresponding limitations in their cost-effectiveness and scalability. Despite Mg2+'s and Li+'s kindred properties, a subtle difference in their electrophoretic mobilities has allowed for the development of the herein proposed new ion separation method for continuous lithium extraction from high Mg2+/Li+ ratio brines utilizing electrokinetic manipulation of ion migrations. This is the first experimental demonstration of a filterless and force-based ion separation method that works by steering ions onto different paths simply by balancing the diagonally formed electric field intensity and flow rate, and realized by introducing a highly scalable electrokinetic system equipped with a multiscale-porous anion exchange membrane. The effects of core operating parameters as well as brine conditions on system performance are elaborated through experimental studies. Remarkably, consistent performance can be achieved in this system regardless of brine conditions by virtue of the filterless lithium extraction mechanism. This work offers a novel strategy to precisely modulate ion migrations in an aqueous solution and furthers progress toward both active ion manipulation and practical and economic lithium mining from different types of lithium-containing brines.11Nsciescopu
Comprehensive Electrokinetic-Assisted Separation of Oil Emulsion with Ultrahigh Flux
No full textMany industries have a significant but largely unmet need for efficient and high-flux emulsion separation, particularly for nanoemulsions. Conventional separation membranes rely on size-based separation mainly utilizing a sieving mechanism plus a wetting phenomenon, resulting in a dramatic trade-off between separation efficiency and separation flux. Herein we address this challenge by adapting electrokinetics to membrane-based separation, using a charge-based mechanism capable of separating even nanoemulsions with a demonstrated separation efficiency of >99% and ultrahigh flux up to 40 000 L/H.m(2). Our device arrests nano-oil droplets, allowing them to coalesce into larger droplets which are then able to be filtered by coarser membranes. This hybrid technology makes electrokinetic-assisted filtration scalable and commercially viable and allows for a better understanding of the multiphysics underlying dynamic separation.11Nsciescopu
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
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