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Swelling behaviour of active clays: the case of an overconsolidated, marine origin clay
No full textThis paper reports the results of one-dimensional compression and swelling tests on an active marine origin clay heavily overconsolidated. The tests were carried out both on undisturbed material and on reconstituted material. Part of the reconstituted material was prepared with distilled water and part with a 1 M NaCl solution. A set of tests was performed by using distilled water as cell liquid and another set by using the salt solution.
The results show that volume changes and swelling pressure are strongly influenced by the composition of the pore liquid as well as by the composition of the liquid the clay is exposed to. In particular, exposure to distilled water causes larger swelling than exposure to the salt solution. The difference is particularly high at low stress level, in which case physicochemical processes rather than mechanical processes seem to dominate the clay behaviour. This suggests that the large difference in water content found in situ between the upper layer (a few meters thick) and the lower material is probably due to osmotic processes of rainwater adsorption
Prove di laboratorio: influenza della composizione del liquido di cella
No full textScopo di questo lavoro è valutare se l'uso convenzionale di acqua distillata può influenzare i risultati delle prove di laboratorio. A tale scopo sono state eseguite prove di taglio diretto, compressione triassiale e compressione edometrica, saturando le celle ed i circuiti sia con acqua distillata che con soluzioni ioniche. La sperimentazione è stata condotta sia su provini ricostituiti che su provini indisturbati di un'argilla molto attiva. E' stata analizzata sia l'influenza del liquido interstiziale che l'influenza del liquido a contatto con la superficie esterna dei provini. I risultati mostrano che la composizione del liquido interstiziale influenza fortemente le proprietà del materiale in ogni tipo di prova. La composizione del liquido a contatto influenza notevolmente i risultati della compressione edometrica fin dalla fase iniziale di determinazione della pressione di rigonfiamento. Nel campo di tensioni indagatao, risentono dell'influenza anche i parametri di resistenza a taglio determinati con prove triassiali consolidate drenate e la resistenza residua determinata con il taglio diretto. Indipendenti dalla composizione del liquido a contatto risultano invece i parametri di resistenza ottenuti con prove triassiali consolidate non drenate se lo stato tensionale sferico ha impedito il rigonfiament
Osmotic softening of overconsolidated clays
No full textThis paper analyses the results of laboratory compression and swelling tests on two strongly overconsolidated clays of marine origin. The tests were carried out on undisturbed specimens taken at various depths from ground surface. During the tests, some specimens were exposed to distilled water and others to a concentrated salt solution similar to seawater. The results show that exposure to distilled water causes much higher swelling. The chemical part of swelling is therefore noticeable; it strongly depends on the stress level and it prevails on the mechanical part under very low values of confining stress. Moreover, it is extremely slow.
On the basis of such results, it is possible to interpret the field trend of void ratio against depth from the ground floor. The large difference between the consistency of the superficial softened layers and that of the underlying hard materials can be interpreted as a physicochemical effect of exposure to rainwater
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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