1,721,107 research outputs found
Specific loss power of magnetic nanoparticles: A machine learning approach
Full text linkA machine learning approach has been applied to the prediction of magnetic hysteresis properties (coercive field, magnetic remanence, and hysteresis loop area) of magnetic nanoparticles for hyperthermia applications. Trained on a dataset compiled from numerical simulations, a neural network and a random forest were used to predict power losses of nanoparticles as a function of their intrinsic properties (saturation, anisotropy, and size) and mutual magnetic interactions, as well as of application conditions (temperature, frequency, and applied field magnitude), for values of the parameters not represented in the database. The predictive ability of the studied machine learning approaches can provide a valuable tool toward the application of magnetic hyperthermia as a precision medicine therapy tailored to the patient's needs. (C) 2022 Author(s)
Magnetic characterization of water suspensions of iron nanoparticles for groundwater remediation
No full textIron nanoparticles are a potential answer to the need for effective in-situ groundwater remediation technologies. Nanoscale iron slurries can be injected in the subsurface allowing to target directly the source of contamination reducing times and costs of remediation. Unfortunatelly the use of this material is strongly hindered by magnetic interactions. Several studies [1] have shown that this system is unstable and tends to separate into water and solid phases after a relatively short time. The colloidal instability is due to the aggregation of the nanoparticles into micrometric dendritic structures which tend to sediment. In this study a magnetic characterization was performed on some samples of iron nanopowders with and without the addition of hydrocolloids to prevent the aggregation and settling. Hysteresis loops have been measured on water dispersed Fe nanoparticles by means of an alternating gradient field magnetometer, at room temperature. The studied systems are characterized by a soft, isotropic magnetic behaviour. However, even though the samples are constituted by nanometer-sized Fe particles, the magnetization processes do not follow a Langevin-type curve, typical of superparamagnetic systems. On the contrary it has been shown that the particles form multi-domain aggregates [2]. An extension of the Stoner-Wohlfarth model can be applied, in which a new switching rule for the local magnetization is postulated, accounting for a nucleation of a new magnetic domain and consequent domain wall displacement within any agglomerate of particles. A so-called cut coefficient r (0 _ r _ 1) parametrizes the nucleation field, being r = 1 the case of magnetization reversal due only to reversible or irreversible rotations (thus corresponding to the “classical” Stoner-Wohlfarth case), whereas when r tends to 0 the domain wall movements become increasingly important in inverting the sample magnetization. Samples with different concentrations of Fe nanoparticles, dispersed in water bare or after coating with hydrocolloids, have been studied through their room temperature hysteresis loops. Proper application of the “extended” Stoner-Wohlfarth model allows an estimation of the effectiveness of the coating to prevent the formation of large aggregates; in fact, if the particles are more separated, their magnetic behaviour should progressively tend towards that of smaller clusters (with a cut coefficient r closer to 1) or even non-interacting particles (with a superparamagnetic behaviour)
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe 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
Low.temperature magnetization and magnetoresistance of the interacting nanogranular superparamagnet Cu95 Co5
No full textVariations on the Author
Full text link“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
Full text linkWe 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
I peptidi generati dalla digestione gastrointestinale conservano la potenziale allergenicità della pasta di grano duro
No full textNegative magnetoresistance in strongly frustrated ferromagnets with nanometric magnetic coherence
No full textDispelling the Myths Behind First-author Citation Counts
Full text linkWe 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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