1,721,460 research outputs found
ISO 16890 and beyond: getting closer to reality
Get PDFThe rationale in developing the ISO 16890 series was to establish a new approach to allow choosing air filters for general ventilation by means of "calculations", like for any other component of air-conditioning systems. Old test methods and classification systems aimed only at comparing products to allow fair competition in the market.
ISO 16890 air filter ratings provide useful information for end users and HVAC designers by introducing a typical particle size distribution of the atmospheric aerosol for calculating the filter impact in cleaning the air.
The next step to work on is the development of an ageing procedure using an ultrafine aerosol, with similar particle size distribution as the one used in ISO 16890, to load air filters during the laboratory test. In this way, it will be possible to predict much better the impact of air filters on the energy used by electric motors in ventilation systems
Performanța filtrării aerului conform noului standard ISO 16890
Get PDFThe purpose of the work is to study of new ISO 16890 standard, that is replaced the current EN 779 standard
Filter Classes Conversion between ČSN EN 779 and ČSN ISO 16890-1
No full textS ohledem na závažnost problematiky a časové zpoždění v převodu tříd filtrů pro všeobecné větrání mezi ČSN EN 779:2012 a ČSN EN IS O 16890-1:2018 jsou v následujících kapitolách stručně uvedeny charakteristické znaky nového zatřídění filtrů, dále shrnuty hlavní rozdíly mezi oběma třídicími systémy a uveden přehled dostupných přibližných převodních vztahů, které mohou přispět k urychlenému uvedení nového systému třídění filtrů do běžné praxe.With respect to the seriousness of the issue and the time delay concerning the filter classes conversion between ČSN EN 779:2012 and ČSN EN IS O 16890-1:2018 for filters for general ventilation, the following chapters briefly present the characteristics of the new filter classification and summarize the main differences between the two classification systems. An overview of the available approximate conversion relationships that can contribute to the accelera ted implementation of the new filter c lassification system is presented
Evaluating the Sensitivity of the Mass-Based Particle Removal Calculations for HVAC Filters in ISO 16890 to Assumptions for Aerosol Distributions
No full textHigh efficiency particle air filters are increasingly being recommended for use in heating, ventilating, and air-conditioning (HVAC) systems to improve indoor air quality (IAQ). ISO Standard 16890-2016 provides a methodology for approximating mass-based particle removal efficiencies for PM1, PM2.5, and PM10 using size-resolved removal efficiency measurements for 0.3 µm to 10 µm particles. Two historical volume distribution functions for ambient aerosol distributions are assumed to represent ambient air in urban and rural areas globally. The goals of this work are to: (i) review the ambient aerosol distributions used in ISO 16890, (ii) evaluate the sensitivity of the mass-based removal efficiency calculation procedures described in ISO 16890 to various assumptions that are related to indoor and outdoor aerosol distributions, and (iii) recommend several modifications to the standard that can yield more realistic estimates of mass-based removal efficiencies for HVAC filters, and thus provide a more realistic representation of a greater number of building scenarios. The results demonstrate that knowing the PM mass removal efficiency estimated using ISO 16890 is not sufficient to predict the PM mass removal efficiency in all of the environments in which the filter might be used. The main reason for this insufficiency is that the assumptions for aerosol number and volume distributions can substantially impact the results, albeit with some exceptions
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Introduction of a new standard for air filters for general ventilation SIST EN ISO 16890
Get PDFV diplomskem delu je predstavljena vpeljava novega standarda za zračne filtre pri splošnem prezračevanju SIST EN ISO 16890, ki je zamenjal prej veljavni standard EN 779. Opisuje tehnične specifikacije, zahteve in klasifikacijski sistem za določitev učinkovitosti filtracije na podlagi drobnih delcev (ePM). V nalogi je predstavljena primerjava med obema standardoma. V drugem delu pa naloga metodološko opiše kriterije in postopke za izbor ustreznega filtra. Predstavljena je testna proga, s pomočjo katere izvajamo meritve učinkovitosti filtracije. Na koncu je opisan še postopek izbire ustreznega filtra glede na onesnaženost zunanjega zraka, ter zahtevano notranjo kakovost zraka. V diskusiji pa je vključen komentar glede prednosti in slabosti posameznega standarda in komentar glede testnih laboratorijev.The dissertation introduces the introduction of a new standard for air filters for general ventilation SIST EN ISO 16890, which replaced the previously valid standard EN 779. The dissertation describes the technical specifications, requirements and classification system for determining filtration efficiency based on the particulate matter (ePM). This paper presents a comparison between the two standards, previosly valid standard and new standard. In the second part the dissertation methodologically describes the criteria and procedures for selecting the appropriate filter. It presents the test rig which help us to measure the effectiveness of filtration. Finally, the process of selecting the appropriate filter with regard to ambient air pollution and the required internal air quality is described. The discussion includes a comment on the strenghts ad weaknesses of each standard and a comment on test labs
Variations on the Author
Get PDF“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
Get PDFWe 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
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