1,720,955 research outputs found
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
IMPACT OF RENEWABLE ENERGY SOURCES IN POWER SUPPLY OF INDIA– A SYSTEM DYNAMICS APPROACH
Get PDFIn this paper, an attempt is made to answer the question: Can renewable energy sources eventually supply India’s electricity needs in the future? In particular, we examine the total potential of renewable energy sources in India and extent to which they can supply these needs. The estimates made here indicate that even with a frugal per capita electricity need of 2000 kWh/annum and a stabilized population of 1500 million by 2025, India would need to generate approximately 3000 TWh/yr. As opposed to this, a systematic analysis of the information available on all the renewable energy sources indicates that the total potential is only around 1000 TWh/yr. It is concluded that in the future as fossil fuels are exhausted, renewable sources alone will not suffice for meeting India’s needs
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
A Comprehensive Study on the Microstructure, Texture, and Mechanical Properties of Mg and its Alloys during Grain Growth
No full textIn the present study, the microstructure, and texture evolution during grain growth of pure Mg and its alloys, such as AM30 (Mg 3 wt.% Al 0.3 wt.% Mn) and AME300 (Mg 3 wt.% Al 0.3 wt.% Mn 0.2 wt.% Ce) have been investigated. The objective of the present study has also been to establish the correlation between microstructure, texture, and mechanical properties in these materials. Hot rolled pure Mg samples were subjected to isothermal annealing at temperatures of 150, 200, 300 and 400 °C for different soaking times ranging from 1 min to 1440 min (i.e., from 1 min to 1 day). A grain growth exponent of n = 13 was observed and the activation energy for grain growth kinetics was found to be 95.6 kJmol. Further, broadening of the normalized grain size distributions, indicating abnormal grain growth, was also observed at all temperatures of annealing. The samples had dominant basal texture before and after annealing. However, alleviation of basal texture was observed in the samples after annealing up to a temperature of 300 °C. Annealing further at a temperature of 400 C formed a strong basal texture in the samples. The mobility of high angle grain boundaries, which is proportional to correlated misorientation distribution, was observed to be responsible for texture strengthening of the material. The boundary mobility changes during grain growth led to the growth of either small or large grains. It was further observed that the growth of small grains caused the formation of basal fiber and large grains led to the weakening of basal texture. AM30 alloy samples were subjected to annealing at temperatures ranging from 200 to 450 °C for different time periods of 1 1440 min respectively. The effects of both annealing temperature, T, and time, t, on the overall grain growth process have been evaluated. A grain growth exponent of n = 9 and activation energy of Q = 105.6 kJmol were observed. It was also observed that the presence of precipitates, such as Mg17 Al12, Al11 Mn4, and Al8 Mn5, in the alloy significantly affect the grain growth kinetics during annealing. Both the volume fraction and the average size of the precipitates decreased as a function of annealing temperature/time. The precipitates were further appeared to be dissolved at a temperature of 450 °C of annealing and this led to the abnormal grain growth of the samples during annealing. The effects of solute drag and dislocation density on the grain growth behavior were found to be insignificant during annealing, as estimated through a mesoscale model based on cellular automata. The strong basal texture in the starting material was observed to be weakened up to 480 min of annealing. However, annealing for 1440 min regained the basal texture which may be attributed due to the abnormal grain growth in the samples. AME300 alloy samples were subjected to annealing at temperatures ranging from 200 to 450 °C for different periods to evaluate the microstructure and texture developments in the alloy. The grain growth exponent of n = 13 and the activation energy for grain growth, Q = 75 kJmol were observed. A large number of precipitates were observed in the samples. They were found to be Mg17 Al12, Al8 Mn5, Al11 Mn4, Al11 Ce3, Al3Ce, Al4 Ce, Mg17 Ce2, Al10 Mn7 Ce2, Mg2 Ce, Mg3 Ce, and Mg12 Ce, as confirmed by electron probe microanalysis (EPMA) and X-ray Diffraction (XRD). The precipitates were further found to be dissolved or disappeared with an increase in the temperature of annealing. As a result, the grain boundary mobility was enhanced during annealing at high temperatures and increased the grain growth of the samples. The initial basal texture in the alloy was observed to be tilted (by ~ 30°) towards the transverse direction of the samples during annealing. Such a texture weakening in the alloy during annealing was attributed to the nucleation and growth of new grains formed in the deformed zone surrounding the precipitates. The correlation between microstructures, textures, and mechanical properties of pure Mg, AM30 and AME300 alloys was further investigated in the present study. The results revealed that the ductility of pure Mg is dependent on the reduction in basal texture intensity. However, its tensile strength is dependent on the average grain sizes of the samples. The same has also been observed in AM30 and AME300 alloys after annealing at higher temperatures of 400 and 450 °C. However, annealing at lower temperatures (i.e., 200 and 300 °C) did not show any correlation between grain size, texture, and mechanical properties of the alloys. This has been attributed to the presence of precipitates in the alloys. It was further found that AME300 alloy had the best combination of tensile strength and ductility compared to AM30 and pure Mg after annealing
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
Development of Al-Fe3Al Composites by Powder Metallurgy Route
Get PDFAluminium based MMCs are one of the most prominent materials due to their low density, high specific strength and stiffness and increased fatigue resistance which make them suitable for various wear and structural applications in various aerospace and automotive industries. Aluminium (Al) is widely used due to its excellent properties such as low density high thermal and electrical conductivity. However, Al has poor wear resistance behaviour, low hardness and poor fatigue properties. This is why Al is very often reinforced with hard materials like carbides, borides, nitrides, oxides and intermetallics. Rising interests in intermetallic compounds is connected with their high strength, corrosion resistance and wear resistance. Among the several intermetallic compounds available iron aluminide (Fe3Al) has been frequently considered for high-temperature structural applications because of their unique physical and mechanical properties. Fe3Al intermetallic compound has a high melting point, high hardness, low density and good oxidation and corrosion resistance. In the present work, an attempt has been made to study the effect of addition of Fe3Al as reinforcement in Al metal matrix composites. Here, in the present research work Al-10, 20, 30 vol. % Fe3Al composites have been developed by powder metallurgy route and their microstructure, hardness and wear properties have been investigated. In the present research work both as-received Fe3Al and Fe3Al developed by 40 h of mechanical alloying (MA) of Fe75Al25 powder followed by heat treatment at 1100oC for a period of 2 h in Ar atmosphere has been used as reinforcement. Nanocrystalline Al developed by milling Al powder for a period of 20 h has been used as the matrix for all the Al-Fe3Al composites developed in this study. The milled powders were analyzed using x-ray diffraction (XRD), scanning electron microscope (SEM), energy dispersive x-ray spectroscopy (EDX), high resolution transmission electron microscope (HRTEM), differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). The 20 h milled nanocrystalline Al was mixed with both the as-received Fe3Al powder and the Fe3Al powder synthesized by MA in different vol. % and compacted under a uniaxial load of 222 MPa and sintered at 500oC for a period of 2 h in Ar atmosphere. The microstructure of the various Al-Fe3Al sintered composites was analyzed using optical microscope, SEM and EDX. The relative density of the various sintered composites was determined by the Archimedes’ principle. Dry sliding wear test of the various sintered composites was done on a ball-on plate tribometer to determine the wear behaviour of the composites. The hardness of the composites was determined using a Vickers microhardness tester. It was found that both the hardness and the wear resisiatnce of the various Al-Fe3Al sintered composites increased with the increase in Fe3Al content
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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