1,720,960 research outputs found
Investigation of the Effect of Shearing Rate on Residual Strength of High Plastic Clay
No full textAkis, Ebru/0000-0001-8417-2405; Yilmaz, Mustafa Tolga/0000-0003-0372-1658The residual shear strength on failure plane is a crucial parameter to be estimated for analysis of an active landslide. This strength must be determined precisely to build a reliable theoretical model for calculations. The multi-reversal direct-shear test is a practical method to determine this shear strength in laboratory due to wider availability of apparatus. The shearing rate is among the factors that significantly affect the precision of test results for clay specimens. However, limits for this rate are yet to be clarified to shorten the duration of multi-reversal direct-shear tests. In this study, two tests series at different shearing rates were performed to investigate the effect of shearing rate on the residual strength of highly plastic clay sample recovered from a landslide area in Northern Turkey. The shearing rates were set to 0.024 mm/min which was decreased to 0.001 mm/min during the last forward shearing phase for the first test series, whereas the rate was fixed to 0.0007 mm/min for the second test series. The residual friction angle determined by these tests was interpreted by using a theoretical analysis of the landslide, and they were compared with the estimations due to empirical relationships given in the literature. It is concluded that, although the rate of 0.024 mm/min is consistent with the recommendations in literature, this rate can yield overestimation of residual shear strength determined in multi-reversal direct-shear tests.Research and Development Department of General Directorate of Highways (KGM)The authors would like to thank the Research and Development Department of General Directorate of Highways (KGM) and the 7th Regional Directorate (Samsun) of Highways for their support to this study
The Effect of Group Behavior on the Pull-Out Capacity of Model Soil Nails in High Plasticity Clay
No full textAkis, Ebru/0000-0001-8417-2405Soil nailing technique is widely used in stabilizing roadway and tunnel portal cut excavations. The key parameter in the design of soil nail systems is the pull-out capacity. The pull-out capacity of soil nails can be estimated either from the studies involving similar soil conditions or from the empirical formulas available in the literature. Particularly, it has been documented placing nails closer than a certain minimum distance results in a reduction in the pull-out resistance of a nail placed in sand. However, this requirement has not been discussed for the nail groups located within clay formations. In order to investigate the influence of nail spacing on the pull-out resistance of nails, a series of laboratory pull-out experiments were performed in clay of high plasticity. The results of these experiments showed a remarkable trend. Specifically, there was a significant reduction in the pull-out capacity of a nail when the spacing between nails two times the nail diameter (2 & Oslash;). In contrast, the pull-out capacity of a nail embedded in clay remained unaffected by neighboring nails, provided the spacing was maintained at six times the nail diameter (6 & Oslash;). In addition, during the conducted pull-out tests, it was observed that the failure mode of a single nail and 6 & Oslash; spaced group nails near the surface results as heaving around the single nail. However, in the case of closely positioned (2 & Oslash; spaced) nails, the affected area following nail failure exhibits distinct characteristics, which operate as a group. This leads to the occurrence of failure in the form of heaving around the group of nails.General Directorate of HighwaysThe writers gratefully acknowledge the support of General Directorate of Highways for this research study. We acknowledge the great support and effort of the staff of Technical Research Department of Highways during this study. Special thanks are due to TDG Company for their support in measurements and recording of the data during experiments
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
The Estimation of the Residual Shear Strength of High Plastic Clays Based on Direct Shear Test Results
No full textLandslides are the most common incidents with a rate of 45% considering the distribution of natural disaster numbers to disaster types. In order to make remedial measures for the landslides, the residual shear strength parameters formed in the shear plane during the landslide must be estimated as close to the reality as possible. These parameters can be determined by multi-reversal direct shear, ring shear tests, back calculations, correlations in the literature by means of physical properties of the soil. The difficulty of predicting the groundwater conditions during landslide is obvious and it directly affects the residual shear strength values when shear strength parameters are determined using the back analysis method. On the other hand, residual shear strength parameters obtained from the literature can give a wide range. Besides, ring shear tests are not commonly performed in laboratories and depending on the type of soil, multi reveral direct shear tests may need to be performed at very low speeds. Relatively long test time adversely affects the practical use of the multi reversal direct shear tests. In this study, the relationship between peak and residual shear strength in normally consolidated high plastic clays was studied within the framework of the above restrictions. Firstly, the empirical correlation between the residual shear strength and the index porperties and peak shear strength was predicted by evaluating the results of the studies in our country's literature. Then, the results obtained from the multi reversal direct shear tests with remoulded high plastic clay samples and the predicted values were compared.Emerging Sources Citation Inde
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
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