1,720,963 research outputs found
Quick assessment of the hot gas layer temperature and potential fire spread between combustible items in a confined space
No full textThe effective management of fire safety requires understanding in advance the resulting conditions of a fire in a confined space. This task is usually achieved by considering several quantitative indicators, establishing threshold limits for each one corresponding to specific hazardous situations and then calculating if such threshold limits are reached. In such a way, it is possible to assess whether or not management conditions are satisfactory. In this work, two main indicators are considered: the hot gas layer temperature and the thermal radiation from the fire. Indeed, the hot gas layer temperature is related with the occurrence of hazardous conditions for people, the spread of the fire to combustible items far from the fire source and hence with the occurrence of flashover and critical conditions for stability of structural elements. On the other hand, thermal radiation from a fire source can be considered as the primary cause of fire spread in pre-flashover conditions, when there is not direct flame impingement and outside the plume, where convective heat transfer is not a principal factor in fire heat transfer. Therefore, in order to estimate if a remote object from the fire will ignite; one must be able to quantify the radiative heat flux received by the target. Both the hot gas layer temperature and the thermal radiation to a target can be assessed by using either analytical equations or fire simulation models. Due to their simplicity and quick use, analytical equations could be suitable for preliminary, rapid hazard assessment. In this work, a comparison between two simple analytical equations and the results obtained using CFD simulations (FDS) for a set of scenarios are presented with the aim of assessing capabilities of the analytical models in foreseen hot gas layer temperature and the thermal radiation from the fire
Rapid estimation of the heat release rate of combustible items
No full textHeat release rate (HRR) from a fire is the most important parameter to describe the potential hazards posed from a fire. Indeed, the environmental consequences of a fire in a confined space depend in large measure on the HRR. Typically, the HRR curves of combustible items are determined in laboratory experiments. For the aim of a rapid hazard assessment, it is infeasible to perform fire experiments on every combustible item inside a given building due to the costs and the time required. Therefore, approximations should be adopted. In this work, we propose a simple method to estimate the HRR curve of a generic combustible item or group of items, through a conventional HRR curve (t-squared growth, peak HRR and linear decay). The conventional curve is drawn considering two main elements: the exposed surface and geometry of the combustible items and a categorization of the constituent materials of the combustible items. Indeed material type and geometry of the combustibles influence the fire growth, while exposed surface and material type are of importance when considering peak HRR. Results are compared with full-scale experiments available in the literature, showing the validity of the approach. The method can be usefully adopted to estimate HRR curves of single as well as multiple combustible items especially in existing activities, where data can be collected from an inspection of the premises aimed at a rapid fire hazard assessment. © Copyright 2016, AIDIC Servizi S.r.l
Quick assessment of explosion hazard in small premises
Get PDFWorkplace safety and emergency procedures require the identification of explosion risks. For this reason, EU Directives as ATEX (Atmosphere Explosives) normative have been specifically issued, with the aims of protecting worker safety, properties, environment and population. Besides, the cited law requires strong expertise and knowledge of the complex science involved in explosion phenomena, which is not straightforward in small and medium enterprises. Indeed, a large amount of published work concerns explosion hazard in large-scale industrial environment, whereas there is a clear lack of studies concerning the risk assessment of explosion in small premises like laboratories, workshops, garages and others. In this work, a management tool for small premises that allows the identification of explosion hazard through a rapid screening of the workplace and the recognition of a limited number of indicators, as the properties of material stored or manipulated and the adopted mitigation systems, has been developed. The tool is essentially based on the maximum quantities of flammable substances and allows the quick assessment of explosion hazard starting from the visual screening or inspection of the workplace. Copyright © 2015, AIDIC Servizi S.r.l
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
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
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe 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
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
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