1,720,984 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
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
OPTIMIZING THE PARAMETERS FOR FRICTION WELDING STAINLESS STEEL TO COPPER PARTS
No full textSt-Cu (stainless steel and copper) parts were friction welded with the aim to optimize the process parameters in the present study. The joints obtained with various process-parameter combinations were subjected to a tensile test. Empirical relationships were developed to predict the strength of the joints using RSM (the response-surface methodology) and the coherency of the model was tested. The tensile properties, microhardness variations, SEM, the EDS analysis and X-ray diffraction (XRD) analysis of the welded specimens were evaluated. It was found, with an ANOVA analysis, that the friction pressure/friction time relation has the largest influence on the tensile strength of the joints followed by the rotational speed. However, it was also found that the formation of intermetallics at the interface is responsible for a higher hardness and lower tensile strength of the friction-welded stainless steel-copper joints
Characterization of properties in friction-welded austenitic-stainless steel and aluminium joints
No full textPurpose - The main purpose of the present study was to evaluate the metallurgical and mechanical properties of dissimilar metal friction welds (FWs) between aluminium and type 304 stainless steel. Design/methodology/approach - One of the manufacturing methods used to produce parts made from different materials is the FW method. Therefore, in the present study, austenitic stainless steel and aluminium parts were joined by FW. Tensile, fatigue and notch-impact tests were applied to FW specimens, and the results were compared with those for the original materials. Microstructure, energy dispersive X-ray (EDX) and X-ray diffraction (XRD) analysis and hardness variations were conducted on the joints. Findings - It was found from the microstructure and XRD analysis that inter-metallic phases formed in the interface which further caused a decrease in the strength of the joints. Research limitations/implications - In this study, the rotation speed was kept constant. The effects of the rotation speed on the welding quality can be examined in future. It is important to note that the FW process was successfully accomplished in this study although it was particularly difficult to obtain the weld due to the large deformations at the interface. Practical implications - Low-density components such as aluminium and magnesium can be joined with steels owing to being cost-effective in industry. Application of classical welding techniques to such materials is difficult because they have different thermal properties. Their welding plays a key part in industrial quality and process control, in the efficient use of energy and other resources, in health and safety. Then, this study will contribute for welded, brazed and soldered materials. Originality/value - The main value of this paper is to contribute and fulfill the influence of the interface on properties in welding of various materials that is being studied so far in the literature
Joining of stainless-steel and aluminium materials by friction welding
No full textThe joining of dissimilar materials is of great importance in industry. Especially, if it is used as the lightest part of the machine parts, materials such as aluminium and magnesium can be joined with different steels. Therefore, in this study, austenitic stainless-steel and aluminium materials were welded using the friction welding method. Optimum parameters for joints were obtained by using a statistical approach, and tensile and micro-hardness tests were applied to the joints. Subsequently, the micro and macro photos of the joints were examined. The joints were examined with EDX (energy dispersive X-ray) analysis in order to determine the phases that occurred during welding. Some of the welds had poor strength due to the accumulation of alloying elements at the joint interface. The obtained results were compared to the results of previous studies
Joining of stainless steel and copper materials with friction welding
No full textPurpose - The purpose of this paper is to investigate mechanical and metallurgical variations at interfaces of commercial austenitic-stain less steel and copper materials welded by friction welding. Design/methodology/approach - In this paper, austenitic-stain less commercial steel and copper materials are welded using the friction welding method. The optimum parameters are obtained for the joints. The joints are applied to the tensile and micro-hardness tests. Then, micro- and macro-photos of the joints are examined. Findings - It is found that some of the welds show poor strength depending on some accumulation of alloying elements at the interface result of temperature rise and the existence of intermetallic layers. Research limitations/implications - It would be interesting to search about the toughness values and fatigue behaviour of the joints. It could be a good idea for future work to concentrate on the friction welding of these materials. Practical implications - Friction welding can be achieved at high-production rates and therefore is economical in operation. In applications where friction welding has replaced other joining processes, the production rate has been increased substantially. Originality/value - The main value of this paper is to contribute to the literature on friction welding of dissimilar materials
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