1,721,021 research outputs found
Source apportionment di PM, campionato in prossimità di una acciaieria tramite SEM-EDX, Caratterizzazione chimica del particolato atmosferico e delle sorgenti.
No full textParticulate air pollution is a mixture of solid and/or liquid particles that vary in size, composition and origin. These particles enter the atmosphere by natural pathways or by the action of man. The undeniable effect of the presence of particulates in the atmosphere is the growing number of people affected from respiratory problems, lung cancer and cardiopulmonary diseases. Source apportionment based on bulk chemical analysis often uses advanced statistical tools for a detailed source categorization. In contrast, in this study the source apportionment is based on properties of individual particles determined by scanning electron microscopy with energy-dispersed spectrometry (SEM-EDS). The receptor site is located near a steel plant in the Apulia Region, South Ital
Individual particle SEM-EDS analysis of atmospheric aerosols in rural, urban, and industrial sites of Central Italy
No full textPM10 samples were collected simultaneously
at three representative areas (urban, industrial, and rural
areas). Their morphology and elemental composition
were determined by scanning electron microscopy
coupled with energy-dispersive analysis (SEM-EDS).
Twenty-four chemical parameters (C, O, Na, Mg, Al,
Si, P, Cd, Cl, K, Ca, S, Sn, Ti, V, Cr, Mn, Fe, Co, Ni, Cu,
Zn, W, and Pb) were determined and three morphological
parameters (area, roundness, and fractal dimension)
were measured by Image Pro Analyzer 6.3. The particles
were classified into ten groups based on morphology
and elemental composition: Ca-rich and metal particles,
soot aggregates, cenosphere, alumosilicates, sea
salt, calcium sulfate, spherical particles of iron, biological
carbonaceous particles, and various. Particles of
natural origin were predominantly found in the coarse
size fraction and particles of anthropogenic origin in the
fine size fraction. The greatest contribution to particulate
matter belonged to aluminum-silicates and calcium-rich
particles. The cenosphere were recognized only in the
coastal urban site, while all the other particles were
present in each site. The coastal industrial site was
characterized by the prevalence of alumosilicates and
Ca-rich particles, due to construction activity in this site
during the sampling period (movement of vehicles,
transport of terrigenous materials, and use of construction
products). The coastal urban site was characterized
by a higher amount of soot and by the presence of
cenosphere, due to the presence of vehicular traffic
Plant regeneration from Cichorium intybus L. leaf explants transformed bt Agrobacterium tumefaciens
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Transient gene expression in bean tissues by high velocity microprojectiles bombardment
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Source Apportionment of PM10 as a Tool for Environmental Sustainability in Three School Districts of Lecce (Apulia)
Full text linkAir pollution is a great threat to the sustainable development of the world; therefore, the improvement of air quality through the identification and apportionment of emission sources is a significant tool to reach sustainability. Single particle analysis, by means of a scanning electron microscope equipped with X-ray energy dispersive analysis (SEM-EDS), was used to identify the morphological and chemical properties of the PM10 particles in order to identify and quantify the main emission sources in three areas of Lecce, a city in the Apulia region of southern Italy. This type of characterization has not yet been performed for the Lecce site, but it is of particular importance to identify, based on the shape of the particles, the natural sources from the anthropogenic sources that are responsible for the serious health effects of the inhabitants. Three primary schools located in peripheral areas of the city were chosen for the sampling: “School 1” (A site), “School 2” (B site), and “School 3” (C site) to carry out a study of the air quality. The A site is characterized by a greater presence of calcium sulphates probably due both to construction activities present during sampling and to reactions between Ca particles and the sulfur present in the atmosphere. At the C site, there is a relative numerical abundance of different groups of particles that present, in the EDS spectrum, an enrichment in sulfur. At the B site, the number of particle groups is intermediate compared to that of the other two sites. With the source apportionment technique, ten emission sources were identified: combustion, soot, industry, soil, carbonates, sea salt, calcium sulfates, SIA, biological particles, and others. In PM10, the three sites are more affected by the soil source, with an effect greater than 60%
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
Dispelling 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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