1,720,955 research outputs found
Field performance of in-service cast iron water reticulation pipe buried in reactive clay
Get PDFField monitoring is an important means for understanding soil behaviour and its interaction with buried structures such as pipeline. This paper details the successful instrumentation of a section of an in-service cast iron water main buried in an area of reactive clay where frequent water pipe breakage has been observed. The instrumentation included measurement of pipe strain; pipe water pressure and temperature; soil pressure, temperature, moisture content and matric suction, as well as the meteorological conditions on site. The data generally indicated that changes in soil temperature, suction and moisture content were directly related to the local climatic variations. The suction and moisture content data indicated that the soil profile at the site down to around 700 mm, and probably down to 1000 mm, is affected by changes in surface weather, while soil conditions below this depth appear to be more stable. Analysis of pipe strain indicated that the pipe behaves like a cantilever beam, with the top experiencing predominantly tensile strains during summer. Subsequently, these trends reduce to compressive strains as soil swelling occurs due to increase of moisture content with the onset of winter
A study of pipe-soil-climate interaction of buried water and gas pipes
No full textIn Australia, buried water and gas pipes are reported to have more frequent failures in hot and dry summers, which suggests that soil shrinkage and thermal effects are the main factors associated with pipe failure. Shrinkage and swelling are common behaviours of soils especially for reactive clays due to seasonal variation of soil moisture content. As a result, the differential soil movement beneath buried pipe can lead to flexural bending and circumferential fracture of the pipe. In addition, seasonal variation of soil moisture content can cause cyclic upward and downward pipe bending and ultimately lead to fatigue failure. However, the relationships between pipe failure, soil behaviour and seasonal climatic change have not been studied in detail. Consequently, the effect of soil moisture content variation on the performance of buried pipes is not clear. This research study is aimed at extending the current knowledge on the interaction between pipes, soils and climate. Field instrumentation was undertaken to study the behaviour of buried cast iron pipes in the natural environment. The collected data confirmed that significant flexural stress was induced by the soil movement on the buried pipe due to the seasonal variation of soil moisture content. Upward and downward bending of the pipe was found to occur at wet and dry seasons, respectively. Regional field measurements of soil moisture content were undertaken in conjunction with field instrumentation to study the seasonal variation of soil moisture content at sites with different soil profiles and geological formations. The 23 sites considered in the study were classified into three categories based on the geological profiles. The study showed that change in soil moisture content was associated with rainfalls and the geological profiles of the site. Variations of soil moisture content can lead to swelling and shrinking of soils and corresponding bending of buried pipes. These data provided the necessary information to understand the likely behaviour of pipes buried in different types of soils. The ground-atmosphere models were used for prediction of soil moisture content variation of the field sites. The Winkler spring models were used to simulate the pipe-soil interaction, and in conjunction with the long term moisture content variation, pipe flexural stress was calculated. Taking into account the deterioration of cast iron pipe strength with time, the relationship between pipe failure probability and pipe age was obtained. This research provides a prediction tool for pipe failure associated with soil behaviour and seasonal climate change. The prediction model can be used to plan for asset management and rehabilitation of the buried pipe networks, thus providing savings on repair of unexpected pipe failures and consequence loss of water and gas services to the communities
A study of pipe-soil-climate interaction of buried water and gas pipes
No full textIn Australia, buried water and gas pipes are reported to have more frequent failures in hot and dry summers, which suggests that soil shrinkage and thermal effects are the main factors associated with pipe failure. Shrinkage and swelling are common behaviours of soils especially for reactive clays due to seasonal variation of soil moisture content. As a result, the differential soil movement beneath buried pipe can lead to flexural bending and circumferential fracture of the pipe. In addition, seasonal variation of soil moisture content can cause cyclic upward and downward pipe bending and ultimately lead to fatigue failure. However, the relationships between pipe failure, soil behaviour and seasonal climatic change have not been studied in detail. Consequently, the effect of soil moisture content variation on the performance of buried pipes is not clear.
This research study is aimed at extending the current knowledge on the interaction between pipes, soils and climate. Field instrumentation was undertaken to study the behaviour of buried cast iron pipes in the natural environment. The collected data confirmed that significant flexural stress was induced by the soil movement on the buried pipe due to the seasonal variation of soil moisture content. Upward and downward bending of the pipe was found to occur at wet and dry seasons, respectively.
Regional field measurements of soil moisture content were undertaken in conjunction with field instrumentation to study the seasonal variation of soil moisture content at sites with different soil profiles and geological formations. The 23 sites considered in the study were classified into three categories based on the geological profiles. The study showed that change in soil moisture content was associated with rainfalls and the geological profiles of the site. Variations of soil moisture content can lead to swelling and shrinking of soils and corresponding bending of buried pipes. These data provided the necessary information to understand the likely behaviour of pipes buried in different types of soils.
The ground-atmosphere models were used for prediction of soil moisture content variation of the field sites. The Winkler spring models were used to simulate the pipe-soil interaction, and in conjunction with the long term moisture content variation, pipe flexural stress was calculated. Taking into account the deterioration of cast iron pipe strength with time, the relationship between pipe failure probability and pipe age was obtained.
This research provides a prediction tool for pipe failure associated with soil behaviour and seasonal climate change. The prediction model can be used to plan for asset management and rehabilitation of the buried pipe networks, thus providing savings on repair of unexpected pipe failures and consequence loss of water and gas services to the communities
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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