1,720,983 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
FINITE ELEMENT ANALYSIS OF HEAT TRANSFER IN THE MIG WELDING OF TYPE 304 STANINLESS STEEL
No full textKaynak havuzunda ısı transferinin, ergime bölgesinin etkili oldugu sıcaklık alanının ve termal dalgalanmaların kaynak metalinde ve ana malzemedeki
makro ve mikro yapıyı etkiledigi bilinmektedir. Bu etki malzemelerin mekanik özelliklerini de etkilemektedir. Bu etkiler ancak deneysel çalısmalar sonucunda incelenebilmekte fakat endüstri uygulamaları buna her zaman imkân vermemektedir. Bu çalısmada, 304 tipi östenitik paslanmaz çeliklerde Metal inert Gaz (MIG) kaynagı sırasında olusan ısıl etkileri incelemek için, dört farklı kaynak hızında parçalar kaynatıldıktan sonra makro ve mikroyapı incelemelerinin yanı sıra sertlik incelemeleri de yapılmıstır. Sonlu elemanlar metodunu kullanan ANSYS programında deneysel sartlara uygun 3 boyutlu
modellemeler yapılmıs ve deneysel sonuçlarla mukayese edilmistir.
Kaynak metalinin sıcaklık ölçümleri 10 farklı noktadan lazer ısını ile sıcaklık ölçen infrared ölçüm yöntemi ile ana malzeme sıcaklık ölçümleri ise K tipi ısıl
çift kullanılarak yapılmıstır.
Deneysel çalısmalarda kaynak arkı basladıgında
kaynak dikisi yapılacak olan 100 mm'lik kaynak dikisi mesafesinin son noktasında henüz daha ark ısısının etkili olmadıgı görülmüstür. Benzer sekilde
kaynak arkı son noktaya ulastıgında baslangıç noktasının hızla soguyarak düsük sıcaklıklara ulastıgı görülmüstür. Bu nedenle sonlu elemanlar tabanlı
ANSYS programında 100 mm'lik kaynak metali dikis mesafesi 10 esit parçaya bölünerek analiz yapılmıstır. Arkın kaynak dikisi üzerinde geldigi alana, lazer
yöntemi ile ölçülen ark sıcaklıgı olan 22000C tanımlanmıs ve bu sıcaklıktan sogumaya baslatılmıstır. Bir sonraki adımda bir önceki adımın sonuç degerleri
baslangıç sartları olarak tanımlanmıstır.
Bilindigi gibi malzemelerin ısıl özellikleri sıcaklıga göre degisim göstermektedir.
Bu sebeple ANSYS programına 304 tipi paslanmaz çelik malzemenin özellikleri tanımlanırken sıcaklıga baglı olarak tanımlanmıstır. Bu özelliklerde malzemenin ergime ve katılasma aralıgındaki enerji degisimi gösterilmistir.
Kaynak esnasındaki ısıl gerilimleri görmek için deneysel olarak elde edilen sıcaklık degerleri kullanılarak ANSYS programında yapısal analizler
yapılmıstır.Deneysel ve ANSYS sonuçları karsılastırıldıgında sonuçların birbiri ile oldukça benzer oldugu görülmüstür. ANSYS sonuçlarının deneysel sonuçlarla uyumlu olması malzeme özelliklerinin, baslangıç ve sınır sartlarının ANSYS programına
çok iyi tanımlanmasına baglıdır.It is known that heat transfer in weld pool, thermal waving and heated zone in
the zone, which is affected by melting, affect the macro and micro structures.
That phenomenon effects on the mechanical properties of materials. These
effects can only be examined by experimental studies. However, industrial
applications may not make possible to examine of these effects in every case. In
this study, 304 type stainless steel was welded in four different welding speeds
by MIG welding, and effects of heat on macro and micro structures and
hardness were examined. 3D simulations in accordance with the experimental
procedure by using ANSYS software were made and the results were compared.
Temperature measurements of weld metal were taken from 10 different points
by using infrared temperature measurement probe. The temperatures of base
metal were measured by using K type thermocouples. The firs measurement,
which was taken just after the first arc, showed that the temperature of the
other end point of welding line, which is in 100 mm distance, was not increased.
Once the weld reached on to the other end point, the starting point of weld line
decreased dramatically to the lower temperatures. For this reason, the
temperature distribution analysis of the weld line was carried out by dividing
the whole weld line into the 10 equal sections for the ANSYS software. The arc
point was determined as to be 2200 oC, which was measured by laser method,
and then the section was left for cooling from this temperature. To analysis the
every section, the result of the previously welded section was taken as the
starting values.
As it is known, the thermal properties of materials vary with temperatures. For
this reason, the properties of 304 stainless steels were introduced to the ANSYS
software depending on temperature. Energy changes between interval of
melting and solidification temperatures were also introduced.
To see the thermal stresses during the welding, structural analyses made in the
ANSYS software using results of temperature obtain as experimental.
When the experimental and modeling results were compared, they were found
as similar. To get a similar result from ANSYS analysis depends on the
introducing of material properties and boundary conditions very well
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
Investigation of wear and microhardness behaviors of AA2196 matrix composite materials reinforced with ceramics produced by powder metallurgy method
No full textThis study aims to investigate the microhardness and wear properties of AA2196 alloy, one of the new generation aluminum-lithium (Al-Li) alloys, reinforced with single and dual (hybrid) ceramic composites. The produced materials were evaluated to improve their properties. The microhardness and wear tests were conducted to assess the mechanical properties of the materials. The results indicate that the dual ceramic reinforced composite materials with AA2196 matrix exhibit superior performance compared to the single compositions. The 12% reinforced hybrid composite alloy (Alloy13) demonstrated the highest microhardness result, while the 2% and 4% reinforced hybrid composite materials exhibited the highest wear resistance. These findings suggest that the microhardness and wear properties of AA2196 alloy can be enhanced through the use of ceramic composites
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