1,721,071 research outputs found
Dimensional analysis for geotechnical engineers
No full textDimensional analysis is an important tool for engineers, aiding the design of experiments and concise expression of the results generated by them. The dimensionless groups, which are the output of a successful dimensional analysis, are usually developed via Buckingham's ‘Pi’ theorem. Because this alone is a necessary, but not sufficient, condition for a solution, difficulties are frequently encountered. This paper presents a general, dimensional analysis algorithm which imposes both necessary and sufficient conditions. Illustrative problems are included, together with a Mathematica program which generates all possible sets of admissible dimensionless groups for a specific problem.<br/
Dimensional Analysis Revisited
No full textDimensionless groups, the output of a successful dimensional analysis, are usually developed via Buckingham's pi theorem. Because this theorem provides a necessary but not sufficient condition for a solution, such a dimensional analysis may, on occasion, appear to fail. The paper presents the necessary and sufficient conditions in a simple form and builds on them to demonstrate how new physical knowledge can augment a 'primitive' set of dimensions to arrive at an optimal number of dimensionless groups. The formulation is used to elucidate the historical Rayleigh-Ria-bouchinsky controversy and a related thermomechanical problem is analysed to demonstrate the complete 'new knowledge' algorithm. Mathematica code is appended which incorporates these ideas and generates the complete set of admissible dimensionless groups for any specific problem
Plastic response of circular footings on sand under general planar loading
No full textData from a set of tests of model circular footings on dense sand are presented. The footings were subjected to a variety of combinations of vertical, horizontal and moment loading. The tests were designed to provide the information necessary to construct a complete model of the footing behaviour, based on the concepts of plasticity theory. In particular, the tests provide detailed information about the shape of the yield surface, and so allow generalization of bearing capacity calculations to cases other than purely vertical loading. Information is also obtained about the hardening law and flow rule appropriate for a plasticity model, and the elastic response within the yield surface.<br/
On the displacement of a traditional retaining wall when first loaded
No full textWhen the dimensions of the base of a retaining wall have been selected by, for example, some form of limit state analysis (Butterfield, 2012) an assessment ought also to be made of the displacement of the wall during its working life. This paper presents a simple rational means of doing so, illustrated by but not limited to, loads imposed during a conventional backfilling process. The analysis presented is an application of a vertical-displacement-hardening plasticity model incorporating nested interaction diagrams as yield functions together with a plastic potential and a hardening rule. The hardening rule, a key component of such a model, is assumed to depend only on the vertical centreline load V0 versus vertical displacement w0 relationship of the wall base. The model predicts that the horizontal, rotational and vertical displacements will be very simply inter-related; a prediction reinforced by the very satisfactory agreement obtained between it and the results from tests on a model footing supported on dense sand
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
A new interpretation of the compressibility of Venetian silty-clay soils
No full textThe latest method for estimating the compressibility of Venetian silty-clay soils was discussed. The secondary compression in the soil column was estimated by analyzing six representative samples of the silty clay. The sand compression values were calculated which provide a rationally supported settlement prediction of 153mm. The method was found to be more efficient in interpreting soil compressibility than the conventional methodology
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
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