1,720,990 research outputs found
Elemental analysis of particulate matter by X-ray fluorescence methods: A green approach to air quality monitoring
Full text linkThis review explores X-ray fluorescence (XRF) spectrometry for elemental analysis of particulate matter (PM) for
air quality monitoring. The introduction presents PM classification based on size and composition, covering
various elemental analysis methods while highlighting the increasing interest in XRF due to its non-destructive,
rapid, and green features. The fundamental concepts of XRF and the experimental configurations commonly used
are discussed, focusing on Energy Dispersive X-Ray Fluorescence (EDXRF) and Total Reflection X-Ray Fluorescence
(TXRF). PM sampling devices and substrate are described, with a specific emphasis on filtering membranes
for EDXRF and reflecting substrates for TXRF. Sample preparation strategies and procedures are presented.
Qualitative and quantitative analysis is described, with a particular focus on the calibration approaches implemented for PM. Finally, the challenges faced by XRF in becoming a recognized reliable analytical technique for PM analysis, comparable to other standardized techniques for PM filters analysis, while capitalizing on its green advantages
Potential of total-reflection X-ray spectrometry for multielement analysis of biological samples using dilution or suspension sample preparation techniques
Full text linkIn most clinical and nutritional studies, it is of significance to know information about the multielemental composition of biological samples. Conventional analysis of biological samples relies upon sample digestion followed by atomic spectrometry detection. This approach is essential for the quantification of ultratrace elements in biological samples. While in other applications it could be of interest to have simpler analytical methods with multielemental capability but involving a minimum sample treatment, reduce the amount of sample and a more cost-effective analysis. In the present contribution, the possibilities and drawbacks of simple sample treatments (i.e., dilution and suspension) in combination with total reflection X-ray fluorescence spectrometry (TXRF) for the analysis of different types of biological samples have been critically evaluated. For that, a set of reference materials or well-characterized biological human fluids (blood, serum, plasma and seminal plasma) and animal/vegetal tissues have been used to estimate the analytical capabilities in terms of limits of detection, trueness and precision of the proposed TXRF methods. The results are based on the authors' experience in analysing biological samples using TXRF, and it is expected that they can be useful for new TXRF users in this field and they can provide a good basis for further application of this technique in clinical studies and other applications dealing with the analysis of biological samples in the future
Dataset on the use of metal hydroxides, instead of flue gas desulfurization residues, to stabilize fly ash by using bottom ash
Full text linkMunicipal solid waste incineration (MSWI) provides significant benefits on waste treatment technologies. Nevertheless some by-products such as fly ash (FA) and bottom ash (Ash) are produced in the incineration plant. Indeed, FA is considered a toxic waste due to the presence of leachable heavy metals (i.e Zn, Cd, Pb, Hg) and metalloid (like As). This data article aims to investigate the reactivity of Ca(OH)2 and Mg(OH)2 as possible substitute of flue gas desulfurization (FGD) residues by mixing with FA, BA and silica fume through a low cost technology. To assess the immobilization process of heavy metals and metalloid, three different samples' compositions were prepared for Ca(OH)2 and Mg(OH)2 series, respectively. Elemental chemical analysis of leaching solutions were carried out by Total reflection X-Ray Fluorescence spectroscopy (TXRF). Data revealed that mixing municipal solid waste ashes with Mg(OH)2 decrease significantly Pb and Zn leachability after two months, and reduce their environmental impact in landfill
Qualità ambientale dei corsi d'acqua nella valle del Khumbu (Sagarmata National Park-Nepal) attraverso indici biocenotici
No full text
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
Variations 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
- …
