1,720,967 research outputs found
A Spreadsheet for Estimating Soil Water Characteristic Curves (SWCC)
Get PDFSWCC can be measured in the lab; however, due to the cost, time, and high variability in the results, empirical equations were developed using multiple regression approaches on databases consisting of a large number of measured SWCCs. The spreadsheet presented herein utilizes different methods that use basic soil properties, such as grain size distribution and Atterberg limits, to calculate the input parameters for van Genuchten and Fredlund and Xing equations. These parameters are required by numerical models, such as SEEP/W, to perform transient seepage analysis. The spreadsheet allows copying the generated curve data points as well as an input into the numerical model. The spreadsheet calculates the SWCCs using seven different methods for comparison. It also compares four closed form models, Gardner (1958), Brooks and Corey (1964), van Genuchten (1980), and Fredlund and Xing (1994), given the model parameters are known
Evaluation of the Land-Climate Interface Boundary Condition on Levee Response Using SEEP/W Software
Get PDFThe focus of this research is to demonstrate the capability of Transient Seepage Analysis and Land-Climate Interface (LCI) to predict the levee response for a short duration and extreme hydraulic loadings. A levee segment named Buck Chute Levee located in between Eagle Lake and the Mississippi River in Eagle Lake, MS is used in this research as a case study. Weather and soil field measurements at this levee have been collected a few years ago as part of a previous study on the levee. For the study presented in this report, the data collected from the period of June 2014 to May 2015 data was used. The weather data recorded included precipitation, temperature, humidity, average wind speed, and total solar radiation. We used the program SEEP/W which is a part of the GeoStudio suite to simulate the seepage flow and the pore water pressure (PWP) response within the levee embankment and, foundation soils to the boundary conditions, and the two bodies of water surrounding it; the Mississippi River and Eagle lake.
Using the collected data, we created a LCI boundary condition that was applied to the embankment surface of the model to simulate the weather impact on the levee. The calibration of the seepage model was achieved by comparing the model total head results to the measurements of three piezometers installed on the landside of the levee. The major outcome of this research study is that the conventional use of the river and lake water level alone is not sufficient to predict the PWP in the levee embankment. LCI should be used in all transient seepage analyses to accurately predict accurate PWP
Interface load: Deformation behavior of landfill liner systems over subsurface cavities.
No full textThe leachate collection system and the double liner required by the EPA for solid and hazardous waste landfills consist typically of a combination of geosynthetics materials and natural or processed soils. This research is conducted to study the load-deformation behavior of a multi layered landfill liner system under stresses imposed by the waste fill. Experimental and analytical work achieved in this research is summarized as follows: (1) Experimental Evaluation of the shear stress-shear deformation characteristics of seven geosynthetic interfaces encountered in landfill lining systems in addition to four geosynthetic materials and three soils. The investigated materials included: Ottawa sand, kaoline clay, and limestone gravel. These soils represent the clay liner, drainage material, and cover soil, respectively, in a landfill. The four geosynthetics included: smooth and textured HDPE geomembrane, Polypropylene nonwoven geotextiles, and solid rib extruded geonet. (2) Development of two constitutive models for the shear stress-shear deformation behavior of the tested interfaces. Parameters of both models are obtained for all interfaces tested in the experimental work. The effect of degree of saturation and compacted soil structure on these parameters is also evaluated and implemented in the model. Furthermore, verification of the two models was achieved. (3) Finite Element (FE) simulation of the load-deformation behavior of a liner system over a trough subsidence. The FE simulations included a study of the effect of subsidence on the mobilized interface shear resistance and associated shear deformations and strains
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
Case Study: Unsaturated Embankment Failure on Soft Soils
Get PDFThis paper describes the application of unsaturated soil mechanics to an interstate connecting-ramp embankment that failed during construction. Specifically, matric suction is incorporated into the calculation of the tension crack (TC) depth induced by desiccation and strain incompatibility and the contribution of matric suction to embankment shear strength. The results are compared with field observations to assess the viability of unsaturated soil mechanics in modeling compacted embankments in stability analyses. Results from this study suggest that using unsaturated shear strength parameters while introducing a TC in the compacted fill yields a reasonable inverse analysis of this interstate embankment. This may be preferred in slope stability analyses to the current practice of using an undrained shear strength (i.e., cohesion) for the unsaturated compacted fill and including a TC to generate a reasonable factor of safety
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