1,720,956 research outputs found
THE EFFECT OF SOLUTION HEAT TREATMENT HOLDING TIME VARIATIONS ON THE MECHANICAL PROPERTIES OF ALUMINUM A-6061 BY THE TIG WELDING PROCESS
Full text linkAluminum and its alloys are metals that are widely used in the engineering field because its have advantages including good formability, relatively high tensile strength, corrosion resistance and a welding process for the joints. General structure, structures that have poor mechanical properties. To overcome this problem, the material that has been welded is heat treated or heat treated according to temperature and time management) which is suitable in addition to good mechanical properties as well as to reduce residual stresses. The purpose of this research is to determine the tensile strength and hardness value of welding joints of Aluminum 6061 with a variation of Holding Time 1, 2, 3 hours in the Solution Heat Treatment process with a temperature of 5000C. The results showed that based on the results of the tensile test, it showed that the holding time affected the value of the tensile strength and strain of the welding joint where the highest tensile test value was at a holding time of 1 hour, while the highest strain value was at a holding time of 2 hours. Then from the hardness test data, it shows that the heating duration or holding time affects the hardness value of the material both in the weld metal, HAZ, and base metal areas. In the weld metal area, the highest hardness value is at a holding time of 3 hours. The HAZ area has the highest hardness value at a holding time of 2 hours, while the base metal region has the highest hardness value at a holding time of 1 hour
KAJI EKSPERIMENTAL PENGARUH BAFFLE PADA ALAT PENUKAR PANAS ALIRAN SEARAH DALAM UPAYA OPTIMASI SISTEM PENGERING
Full text linkHeat exchangers or heat exchangers are tools used to change the temperature of the fluid or change the fluid phase by exchanging heat with another fluid. In a heat exchanger, the ability to exchange heat is largely determined by the type of fluid flow and fluid passing through the heat exchanger. The use of heat exchangers in the field of drying is now a necessity to overcome the problems of drying productivity. The purpose of this study was carried out to determine the effectiveness of the heat exchanger experimentally based on directional flow by comparing construction using baffle and without using baffle in an effort to optimize the drying system. The research method was carried out by fabricating 2 units of heat exchangers and by field testing. The test data obtained are the input and output temperatures of the heating fluid flow and cooling fluid flow and flow velocity. Based on preliminary research data shows that the use of baffle affects the increase in temperature on the heat exchanger, where at the fresh air outlet that does not use baffle produces a temperature of 72oC while the baffle produces 88oC with the Log Mean Temperature Difference heat exchanger without using a baffle higher than heat exchanger that uses a baffle guide blade. This can illustrate that the smaller heat losses are wasted so that the absorption of heat by the reverse system will be higher
The Effect of Holding Time on Stress Relief Annealing Process to Hardness of Carbon Steel SA.106 Grade B After Welding
Full text linkStress relief annealing (SRA) is a process of releasing residual stresses contained in the material due to the welding process. The need for SRA is due to heterogeneous changes in the microstructure when the material is exposed to the heat of welding so that it will cause the mechanical properties of the material to change. One of the mechanical properties that experience significant changes is hardness (hardness value) because it can experience an increase. Therefore it is necessary to decrease the hardness value through a heat treatment SRA that takes into account the appropriate holding time. The purpose of this study was to determine the effect of holding time variations on the value of the welding material hardness for the carbon steel case SA.106 Gr.B. During this time after welding SA106 material specifically under 19 mm thickness is not heat treatment after welding even though the welding effect will change the properties of this material, so it is necessary to heat treatment with certain holding time variations to determine its effect on the mechanical properties of the material. The welding process uses SMAW with E7018 electrodes. Specimen heating is carried out in a heating oven to a constant temperature of 650oC with variations in the heating time of 15 minutes, 30 minutes, and 45 minutes. Furthermore, hardness testing is done by testing the base metal area, heat affect zone, and weldment. The results that SRA greatly influenced the hardness value of a welded material, based on testing the highest hardness value in the SRA heat treatment was obtained at a holding time of 45 minutes with a hardness value on the base metal of 67 HRC (BM), HAZ area of 65.25 HRC, and weldment area of 64.42 HRC. But at the holding time for 45 minutes, the value of material hardness tends to be more uniform compared to other variables
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
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