1,721,015 research outputs found
Performance evaluation of a gaseous pollution control device suitable for in situ heating, ventilation and air conditioning applications
No full textAir pollution is a ubiquitous problem plaguing global citizens with decreased quality of life. Pollutants are created both indoors and out and contribute to poor indoor and ambient air quality. Indoor air purification technologies have been created and are successful in removing particulate matter, though there are severe limitations and environmental repercussions with existing technologies used to eliminate gaseous pollutants. To address this need, research and development led to the creation of a gaseous pollution control device which uses a patented photocatalyst capable of simultaneously destroying both volatile organic compounds and nitrogen oxides over extended time durations. A laboratory-scale prototype was built and a rigorously tested to evaluate the removal of nitric oxide and select volatile organic compounds (formaldehyde, ethanol and limonene). The test campaign used various velocities, surface conditions, length scales, light power outputs and pollutant compositions to generate a statistically relevant data set for evaluating performance. Performance evaluation of the two prototype units produced reduction efficiency between 550–60% for formaldehyde, 60–85% for nitric oxide, 80–99% for limonene, and 100% for ethanol, over the air velocity range of 0.5 to 2.0 m s−1. Removal efficiency of the unit appears to be most dependent on the molecular structure (i.e., bond strength) of the pollutant and the pollutant residence time within the unit (i.e., velocity or having multiple units in series). Additionally, there are opportunities for optimizing performance of the units through controlling power output of the illumination source or periodically performing a simple water rinse.Canadian Government National Science and Engineering Research Council (NSCER)Government of Ontario Graduate ScholarshipUniversity of Guelp
Nitrogen Oxide (NOx) emissions as an indicator for sustainability
No full textEnvironmental data and research illustrate that global warming, normally assessed through carbon dioxide (CO2) and greenhouse gas (GHG) emissions, is a critical element in environmental sustainability and that a shift to decarbonized energy sources is necessary to preserve the environment for future generations. The challenge is that overall global sustainability is more complex than solely focusing on global warming or the environment.
As a potential alternative, NOx emissions are explored as a potential surrogate for CO2 and GHG emissions and as an indicator for decarbonization. An added benefit of using NOx is that it has strong correlations with each pillar of sustainability, and therefore can offer a more encompassing view. Global and country specific NOx emissions, between 1990 and 2015, are analyzed in a format paralleling the three pillars. Trends show that, while NOx emissions are increasing, there are improvements in both societal and economic emission intensities. It is also demonstrated that there is no net movement towards decarbonization, and that a paradigm shift will be necessary to achieve the emissions reductions required. As well, human development index appears to be tied to the change in per capita emissions of NOx over the study period. Overall, NOx is demonstrated to be a robust and potentially more effective surrogate for CO2 and GHG emissions in estimating fossil fuel emissions and gauging movement towards decarbonization. The added interconnectedness of NOx with all three pillars makes it an excellent indicator for tracking progress towards overall sustainability
An Evaluation of Risk Ratios on Physical and Mental health correlations due to Increases in ambient Nitrogen Oxide (NOx) concentrations
No full textNitrogen oxides (NOx) are gaseous pollutants contributing to pollution in their primary form and are also involved in reactions forming ground-level ozone and fine particulate matter. Thus, NOx is of great interest for targeted pollution reduction because of this cascade effect. Primary emissions originate from fossil fuel combustion making NOx a common outdoor and indoor air pollutant. Numerous studies documenting the observed physical health impacts of NOx were reviewed and, where available, were summarized using risk ratios. More recently, the literature has shifted to focus on the mental health implications of NOx exposure, and a review of the current literature found five main categories of mental health-related conditions with respect to NOx exposure: common mental health disorders, sleep, anxiety, depression, and suicide. All the physical and mental health effects with available risk ratios were organized in order of increasing risk. Mental health concerns emerged as those most influenced by NOx exposure, with physical health impacts, such as asthma, only beginning to surface as the fourth highest risk. Mental health conditions occupied seven of the top ten highest risk health ailments. The results summarized in this narrative review show that there are clear positive correlations between NOx and negative physical and mental health manifestations, thus strengthening the argument in support of the reduction in ambient NOx levels.Canadian Government National Science and Engineering Research Council (NSERC)Government of Ontario Graduate Scholarship (OGS)University of Guelp
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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