1,720,953 research outputs found
Studies on Strength, Durability, and Structural Properties of Copper Slag Aggregate Concrete
No full textConcrete is the most versatile construction material because it can be designed to withstand the harshest environments while taking on the most inspirational forms. Engineers are continually pushing the limits to improve its performance with the help of innovative alternative aggregate and supplementary cementitious materials. Aggregates are usually obtained from natural rocks, either crushed stones or natural gravels, and comprise as much as 60% to 80% of a typical concrete mix. So they must be properly selected to be durable, blended for optimum efficiency, and also should exhibit a good bond with reinforcement after hardening. Initially, these are generally thought of as inert fillers within a concrete mix, but a closer look reveals the major role and influences aggregate plays in the properties of both fresh and hardened concrete. The rapid growth of industrialization gave birth to numerous kinds of industrial slags that are environmentally hazardous and create problems with storage and disposal. The consumption of these slags as a replacement for aggregates in concrete not only helps in saving natural resources but also helps in making environmentally friendly construction material. Hence, the management and utilization of industrial slag have become important for some researchers in the past couple of decades. Presently in India, due to limited modes of practices of utilization, a huge amount of copper slag is dumped in yards of each production unit and engaging important agricultural land and grave pollution to the whole environment. Currently, worldwide about 57 million tonnes of copper slag is generated annually with India contributing 12-16.5 million tonnes. Barely dumped copper slag pollutes the nearby soil and the adjacent water bodies ultimately contaminating groundwater, lakes, streams, rivers, or coastal waters. On the other hand, this copper slag is often mixed into municipal waste and hinders making accurate assessments difficult. An efficient approach to overcome these problems is slag utilization, which minimizes land disposal. The disposal of copper slag is an environmental challenge globally, and the only viable solution for its mass disposal is its use in the construction industry, especially for concrete production. However, the performance of a concrete structure is dependent upon the properties of the components such as cement, coarse aggregate, fine aggregate, and superplasticizer along with several other factors. Physical and chemical characterization of the slag is a deciding factor in its utilization as fine aggregate as recycled construction materials, etc. Basic physco-chemical properties like specific gravity, fineness modulus, particle size distribution, chemical composition, and strength activity index of both copper slag and natural sand are studied. Hence, the evaluation of copper slag aggregate concrete (CSAC) properties is essential for the quality construction of the concrete structure. The present research is an effort to study the engineering properties of CSAC which include strength properties, durability properties, and structural properties, establish the correlation among these properties, and quantify variability associated with different strength properties over a longer curing period of 90 days. Basic fresh concrete properties like workability and rate of bleeding, hardened concrete strength properties like compressive strength, split tensile strength, flexural strength, water absorption, void content, microhardness, and microcrack analysis are studied on a large no of CSAC samples and the obtained result is checked for its appropriateness in eminence construction. Better particle packing and due to the presence of natural pozzolana (Class N) in copper slag which strongly influences all the strength properties. Durability properties like slake durability, abrasion resistance, accelerated corrosion test, rapid chloride penetration test, and carbonation test are also studied on a large number of CSAC samples. Some efforts have been made to test the suitability of copper slag use in designing durable concrete. However, the evaluation of all these strength and durability properties needs admittance to polished instruments, which is normally not obtainable in the majority of construction sites. This demands the development of a substitute technique that could deliver first-hand information on the strength, durability, and quality of CSAC without the need for any huge testing apparatus. For this resolve, the correlation between the strength, durability, and other easily measurable parameters is studied and mathematical models are developed to predict the CSAC properties using other parameters through experimental results and statistical correlation. These models can be used as a quality control tool for CSAC production at the actual construction site. A proper mechanical interlocking between cement and aggregate results in good bond strength of structural concrete. If the aggregate possesses its own pozzolanic property, the interlocking improves due to secondary hydration products on the aggregate surface. Both strength and durability of concrete are influenced by the bond strength to a large degree. The strength properties of CSAC can show a significant variation because of several influencing factors like source and proportion of constituent materials, workmanship, and curing condition among others. Quantification of this uncertainty is essential for the reliability-based limit state design of masonry structures. Safety and strength assessment of structures made of CSAC often requires modelling the uncertainty of its properties. The present study investigates the variability associated with compressive strength, shear-, split tensile-, and flexure tensile-bond strength of copper slag aggregate concrete were analysed and proposes the most appropriate model for its statistical distribution. Four probability distributions are considered to conduct the three goodness of fit tests, namely Kolmogorov-Smirnov, Kolmogorov-Smirnov-Lilliefors, Anderson-Darling, and Chi-Square (CS) tests. The analysis shows that conventionally assumed normal distribution is not suitable for describing the strength properties of copper slag aggregate concrete as the experimentally obtained strength data is not symmetrical about its mean value. The best-fitted distribution functions that perform well in describing the variability in different strength properties of copper slag aggregate concrete are recommended. A case study on the seismic risk of a typical reinforced concrete framed building with CSAC is performed considering different probability distribution functions. The results of the case study indicate that the choice of the probability distribution of the random variables influences the seismic risk assessment of structures significantly and consideration of the appropriate distribution function is vital for the precise estimation of seismic risk
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
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
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
Author Under Sail The Imagination of Jack London, 1893-1902
No full textIn Author Under Sail, Jay Williams offers the first complete literary biography of Jack London as a professional writer engaged in the labor of writing. It examines the authorial imagination in London's work, the use of imagination in both his fiction and nonfiction, and the ways he defined imagination in the creative process in his business dealings with his publishers, editors, and agents. In this first volume of a two-volume biography, Williams traverses the years 1893 to 1902, from London's "Story of a Typhoon" to The People of the Abyss. The Jack London who emerges in the pages of Author Under Sail is a writer whose partnership with publishers, most notably his productive alliance with George Brett of Macmillan, was one of the most formative in American literary history. London pioneered many author models during the heyday of realism and naturalism, blurring the boundaries of these popular genres by focusing on absorption and theatricality and the representation of the seen and unseen. London created an impassioned, sincere, and extremely personal realism unlike that of other American writers of the time. Author Under Sail is a literary tour de force that reveals the full range of London as writer, creative citizen, and entrepreneur at the same time it sheds light on the maverick side of machine-age literature.Intro -- Title Page -- Copyright Page -- Dedication -- Contents -- Acknowledgments -- Introduction -- 1. Spirit Truth -- 2. From Absorption to Theatricality and Back Again -- 3. "I Will Build a New Present" -- 4. Sons as Authors -- 5. Fathers as Publishers -- 6. The Daughter as Author -- 7. Lovers as Authors -- 8. At Sea with the Family -- 9. Yellow News, Yellow Stories -- 10. The Return Home -- Notes -- Bibliography -- Index -- About Jay WilliamsIn Author Under Sail, Jay Williams offers the first complete literary biography of Jack London as a professional writer engaged in the labor of writing. It examines the authorial imagination in London's work, the use of imagination in both his fiction and nonfiction, and the ways he defined imagination in the creative process in his business dealings with his publishers, editors, and agents. In this first volume of a two-volume biography, Williams traverses the years 1893 to 1902, from London's "Story of a Typhoon" to The People of the Abyss. The Jack London who emerges in the pages of Author Under Sail is a writer whose partnership with publishers, most notably his productive alliance with George Brett of Macmillan, was one of the most formative in American literary history. London pioneered many author models during the heyday of realism and naturalism, blurring the boundaries of these popular genres by focusing on absorption and theatricality and the representation of the seen and unseen. London created an impassioned, sincere, and extremely personal realism unlike that of other American writers of the time. Author Under Sail is a literary tour de force that reveals the full range of London as writer, creative citizen, and entrepreneur at the same time it sheds light on the maverick side of machine-age literature.Description based on publisher supplied metadata and other sources.Electronic reproduction. Ann Arbor, Michigan : ProQuest Ebook Central, YYYY. Available via World Wide Web. Access may be limited to ProQuest Ebook Central affiliated libraries
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