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Utilization of Industrial Solid Wastes for Synthesis of Inorganic Polymer as a Soil Stabilizer
No full textSoils need to be stabilized to improve its geo-engineering properties before any construction of infrastructures. Conventional soil stabilizers such as cement and lime have environmental issues and uneconomical. Geopolymers are the new generation binder that has attracted considerable interest in modern construction industries due to their high engineering performance, less environmental impacts and cost-effectiveness. An investigation is made to explore the efficacy of geopolymer prepared by sodium hydroxide activated fly ash-slag in stabilizing the granular soil through a set of experimental studies.
The physical, mechanical and chemical properties of geopolymers are greatly influenced by the synthesis parameters. The fresh and hardened properties such as normal consistency, setting time, soundness, drying shrinkage, flow and compressive strength of the geopolymer paste and mortar are reported. The influence of synthesis parameters on the unconfined compressive strength of the geopolymer; synthesized under different processing conditions is investigated. The microstructural analysis is also made to correlate the reaction products with the observed strength. Statistical analyses are carried out to check the significance of the factors affecting the synthesis process. Also, mathematical relationships are established for factors influencing the mechanical behavior of the synthesized geopolymer. The compaction characteristics, unconfined compressive strength, bearing resistance, permeability characteristics, durability under wetting-drying, freezing thawing cycles and decay under chemical attacks of geopolymer modified granular soil are investigated experimentally in order to assess its suitability as a geotechnical construction material. Also, the effect of delayed compaction on density and strength has also been studied. Microstructural analysis has been carried out and correlated with the strength development.
The test results reveal that the dissolution of alumino-silicates is highly influenced by the alkali content and the reactive component of the source material. The experimental results indicated that the physico-mechanical properties of geopolymer binders are similar to that of conventional cement and are greatly influenced by the composition of the source material, concentration of the activator and processing conditions. The major reaction products were the hydrates of calcium and/or sodium based alumino-silicates and those were intensified with curing temperature and duration. Raw materials are optimized by the design of experiment and the fitted model shows a good relation with the experimental data. Based on the test results of geopolymer stabilized soil, a maximum unconfined compressive strength of about 7 MPa is attained. California bearing ratio ranging from 52 to 416% are obtained at different geopolymer contents and curing conditions. The geopolymer stabilized granular soil showed excellent stability against repeated wetting-drying, freezing-thawing cycles, slaking fluid and aggressive chemical environment. The microstructural developments in geopolymer stabilized granular soil are greatly influenced by the geopolymer content and curing period signifying the formation of hydration and geopolymeric reaction products
Geo-engineering properties of lime treated plastic soils
Get PDFFor a long time, we are facing problems like failures of small and big structures. The biggest problem behind this is swelling soils. This is very unstable soil. Its property varies from hard to soft and dry to wet. It exhibits swelling and shrinkage with different water content. As a result, many structures usually face excessive settlement and differential movements, which causes damage to foundation systems and other structural elements. We are aware about this situation for a long time, but unable to make improvements due to absence of technologies till now. Through physico-chemical modifications, lime can control the plasticity, swelling and shrinkage of soil effectively. Also, lime can stabilize soil through cementation which increases strength and stiffness remarkably. In this work the plasticity characteristics, swell shrinkage properties, compaction characteristics and strength properties of plastic soils with a wide plasticity range treated with lime has been evaluated experimentally. Based on the unconfined compressive strength the optimum lime content of soils has been found out. For this purpose, commercial high plastic clay (i.e. bentonite) having liquid limit of 340% is mixed with different proportions to a residual soil having liquid limit 34% and four different soils were synthesized over a wide range of plasticity. The physical properties of raw soils were found out. The four soils were amended with different lime content and the index properties as well as engineering properties have been studied by conducting relevant experiments conforming to Indian standard code of practice. Based on the experimental results it is observed that the liquid limit and plasticity reduces as lime content increases, swell and shrink characteristics decreases with lime content. Also, lime has a significant effect on strength
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
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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