1,720,955 research outputs found
Fire Safety of Grounded Corrugating Stainless Steel Tubing in a Structure Energized by Lightning
No full textCorrugated stainless steel tubing (CSST) has been used for more than 20 years as a replacement for conventional black iron gas piping. CSST has a thinner tubing wall and is susceptible to damage from lightning activity when discharges enter a structure, potentially resulting in perforation of the CSST wall and fire ignition. Grounding has been promoted by CSST manufacturers as a solution to this problem. We use modeling and simulation of voltage potentials and arc currents to evaluate the effects of grounding on the voltage potential across CSST, which can result in arc initiation, and charge through the arc, which can result in melting and perforation of the CSST wall. Our results show multiple scenarios where a 10 kA 10 × 350 s current waveform with 1 Ω grounding of the CSST still results in voltages greater than the arc initiation threshold of 25 kV and charge through the arc greater than 1.2 C, the perforation threshold we measured. For the case where lightning enters the structure through an outdoor light fixture or chimney, the presence of a grounding wire increases the charge through the arc from 0.13 C to 2.22 C. These results indicate that good grounding of CSST will not necessarily prevent arc initiation nor perforation of the CSST wall by lightning. Good grounding may in fact exacerbate the problem of lightning damage to CSST depending on where lightning enters the building and the electrical parameters of the path to ground
Relating Noninvasive Cardiac Output and Total Peripheral Resistance Estimates to Physical Activity in an Ambulatory Setting
No full textThe prevalence and cost of heart disease indicate the need for better methods of detecting, diagnosing and treating this pervasive problem. Appropriate monitoring outside of the hospital can potentially lead to earlier diagnosis and reduced costs. We use electrocardiogram (ECG) and continuous arterial blood pressure (ABP) data collected in an ambulatory setting to examine two important cardiovascular quantities, namely cardiac output (CO) and total peripheral resistance (TPR), over a range of physical activities. CO and TPR can be estimated from heart rate, pulse pressure and mean arterial blood pressure, which in turn are directly obtained from the ECG and ABP signals. More specifically, we employ a wearable cardiac and motion monitor designed by colleagues at MIT to simultaneously record ECG and 3-axis acceleration to onboard memory. The acceleration data is used to generate an estimate of physical activity at each time point. Additionally, we use a Portapres continuous blood pressure monitor to concurrently record the ABP waveform. We present representative results from data collected in a controlled ambulatory setting. Heart rate, mean ABP, CO and TPR responses to physical activity are generally consistent with what might be expected from cardiovascular physiology. The longer-term challenge is to correlate the dynamic behavior of these quantities with the state of cardiac health.Texas Instruments IncorporatedUnited States. Dept. of Defense National Defense Science & Engineering Graduate Fellowship (NDSEG) Program
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
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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