1,720,965 research outputs found
Outdoor and indoor measurements of number particles size distributions and equivalent black carbon (EBC) at a mechanical manufacturing plant
Full text linkHuman exposure to air pollution is of great concern, especially in working places, where many people spend a lot of time. This work describes results obtained during a measurements campaign (February–July 2021) of aerosol number size distributions and equivalent black carbon (EBC), inside and outside a mechanical manufacturing plant, in Southern Italy. Outdoor and indoor EBC data are highly correlated (R2 = 0.98) suggesting the same sources: vehicular traffic, domestic heating and agricultural waste burning (February–April). In these months the outdoor Angstrom absorption exponent (AAE) was highly oscillating (0.64–1.62), with reduced oscillations (0.9–1.5) during warmer months. These last values suggest the influence of a diffuse cloud of aged smoke due to uncontrolled and extended wheat biomass burning, lasting about one month, in the nearby Apulia region. A good correlation between outdoor EBC and NC1 (particles number with D ≤ 1 μm) confirms that EBC has a high contribution to the aerosol size distribution. The same profile of number size distributions in both configurations indicates the same sources but, during cold months, the outdoor ones are characterized by higher values than the warm months, especially in the fine particles range. During working and non-working days, a reduction of indoor particles number concentration over the whole size range is observed throughout the weekend, suggesting manufacturing activities as one of the sources. Scanning electron microscope (SEM) analysis of outdoor and indoor spare internal filters shows the presence of metal particles indicating inside particles are being transported outside
A two-year database of BC measurements at the biggest European crude oil pre-treatment plant: a comparison with organic gaseous compounds and PM10 loading
No full textA two-year data-set of black carbon (BC) measurements collected in a site in South Italy close to the biggest European pre-treatment plant (COVA) of crude oil has been studied. The area named Val d'Agri, in Basilicata Region, is also crossed by the main road SS598. Data have been collected by using a 7 wavelength aethalometer allowing the measurement of equivalent black carbon (EBC) content, the estimation of Ångström absorption exponent (AAE), and the detection of organic fraction presence through UVPM (UV-absorbing particulate matter) quantity. Data have been analyzed to distinguish seasonal behaviors and characteristics of carbonaceous aerosols. No evident seasonal patterns have been observed for EBC concentrations with a mean value of 643±415ng/m3 and a large short-term variability, with frequent periods (few days or few weeks) of intense emissions associated to COVA activities. EBC averaged daily trends show two main peaks, one in the morning and one in the evening suggesting a contribution of traffic as a background source of BC on a long-term basis, due to the SS598 passing near the measurement site. On a four month period in 2013, a comparison with co-located PM10 concentrations data has been carried out showing a relevant contribution of EBC to the total particle loading at the site. Unlike EBC, AAE shows higher values (maximum value 1.3±0.3) during cold periods and lower values (minimum value 0.9±0.2) in the warmer seasons. Anti-correlation has been observed when comparing AAE with both solar radiation and temperature. In addition, enhanced values during night time for AAE average daily patterns have been observed despite the seasons, suggesting relevant additional sources of organic carbon other than traffic related to COVA emissions during the year. Moreover a good agreement, on a short-term basis, has been found among UVPM, benzene, toluene
Long-Term Characterization of Indoor Air Quality at a Research Area Building: Comparing Reference Instruments and Low-Cost Sensors
No full textAn integrated approach to characterize long-range transported dust.
Full text linkAn integrated approach, combining columnar and in-situ measurements was used to characterize
optical and micro-physical properties of atmospheric aerosols under the advection of Saharan dust airmasses in a site in South Italy. Background and dust-affected radiometric measurements were
compared to study their radiative properties. Starting from these radiometric measurements, a source
identification technique based on the aerosol components from OPAC (Optical Properties of Aerosols
and Clouds) model revealed that mineral dust, soot, water soluble, sea-salt accumulation and sea-salt
coarse contribute in a similar way to the solar radiation attenuation. SEM analysis on atmospheric
particulate collected at the ground pointed out that crustal elements characterize particles on both fine
and coarse stages. Dust particles embedded in soot chains and traces of industrial particles were also
detected
Effects of polluted air-masses advection on atmospheric particles in a semi-rural site in south Italy by SEM-EDX analysis
Full text linkThe variation of aerosol properties under polluted air masses advection was studied in a semi-rural site in South Italy, by means of SEM-EDX analysis performed on particles collected on 13-stages impactor filters. Radiometric measurements, HYSPLIT back-trajectories and NAAPS maps helped to choose four measurement days of polluted air mass circulation, two of them collected in the warm season (31 July 2008, 16 September 2010) and two in the cold one (16 April 2009, 18 March 2010). Polluted aerosol characteristics were compared to those under background (BG) conditions (8 February 2011), highlighting differences in the particles chemical and morphological properties. One of the signatures of the air mass transport in the coarse fraction was the higher content of particles containing S, i.e., S-reacted, (27.5% on average) in comparison with BG conditions (1%). Two main sources of transported aerosols were identified: industrial processes and biomass burning, with fly ash, metal and S-rich particles in the first case, and K-salts and nitrate-coated Ca-bearingparticles in the second. Single particle analysis on the coarse fraction allowed large agglomerates of soot to be identified, with inclusions of silicate particles rich in Cu and Zn, Ca-S, fly ash and metals particles that are a clear indication of extensive modifications of aerosol size, chemical composition and, likely, radiative properties. In finer stages (EAD ≤ 0.94 μm) concurrent collection of organic and inorganic particles originated an agglomerate state matter mainly characterized by K and S for polluted conditions and by K only for BG
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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