1,720,982 research outputs found
Analysis of the problems connected to the sinking of microTBMs in difficult grounds
No full textIn spite of the many advantages offered by micro-tunnelling, significant problems of a technical nature can be encountered when the excavation machine tends to sink under its weight in poor sandy-silty soils and there is deviation from the theoretical advancement direction. This work presents a new calculation procedure that is able to evaluate the settlements and rotations of a Microtunnel Boring Machine (MTBM) and, therefore, to signal the danger of sinking of the excavation machine. The procedure involves the combined use of the hyperstatic reaction method (with a Winkler approach) and of a finite difference numerical method. A parametric study developed with the proposed procedure for poor grounds, from the geotechnical point of view, has led to useful indications on the courses of action to take (integrative structural works or ground reinforcement) when it is possible that the phenomenon of machine sinking could occu
Micro-calorimetric studies of NO2 adsorption on Pt/BaO-supported on Γ-Al2O3 NOx storage and reduction (NSR) catalysts—Impact of CO2
No full textThe adsorption of NO2 on Pt/BaO/γAl2O3 catalyst has been investigated by micro calorimetry at atmospheric pressure, NOx storage tests and temperature-programmed desorption (TPD). The heat of adsorption of NO2 (ΔHads(NO2)) was determined over a wide range of NOx coverages, as the catalyst was exposed to 500/900 ppm NO2 in the absence/presence of 5% CO2 in the range of 423–773 K. The temperature dependent changes of ΔHads(NO2) verified the presence of energetically different NOx storage sites with different binding strength. The ΔHads(NO2) was found to follow a linear correlation versus temperature, ranging for example from −134.5 to −178.8 kJ/mol for NOx storage over Pt/BaO/γAl2O3 at 423–673 K. Thus, at high temperature mostly strongly bound nitrates were formed, while at lower temperature more loosely bound species were also present. Interestingly, the heat of adsorption was higher when using higher NO2 concentration, indicating more bulk barium nitrate formation. This is consistent with the TPD data where a clear high temperature peak was visible after adsorption using 900 ppm NO2 at 423 and 473 K, which was not the case for 500 ppm NO2. Moreover, the micro-calorimetric data also provided evidence in support of the detrimental effect of CO2 on the NOx uptake process. The heat released during the NOx storage in 500 ppm NO2 + 5% CO2 was determined to be significantly reduced ca. −97.8 kJ mol−1 at 423 K, but ca. −134.5 kJ mol−1 without CO2. Furthermore, our results show that it is critical to measure heat of adsorption for surface compounds since they are significantly different compared to thermodynamic data for bulk materials
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
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
- …
