1,720,961 research outputs found
Characterization of the Co-Flow Jet Effect as One of the Flow Control Devices
Full text linkThe computational study discusses the application of the co-flow jet technique as a fluid flow control device on the NACA 0015 airfoil. The numerical equation used is the RANS equation with the k-ε turbulence model. There are three variations of the mesh proposed in this paper. The first variation is a fine mesh with 100,000 elements. The second variation is a medium mesh with 50,000 elements. Meanwhile, the third variation is coarse mesh with 25,000 elements. Based on the mesh independence test results, the mesh with the lowest error value is the fine mesh. Co-flow jet is proven to control fluid flow on the upper side of NACA 0015. Co-flow jet can also improve the aerodynamic performance of NACA 0015 by increasing Cl and decreasing Cd. The increase in Cl was 114% and the decrease in Cd was 24%. The fluid flow separation on the upper side of the airfoil can also be handled well by the co-flow jet
Analisis Motor Listrik Tipe Synchronous dengan Metode Komputasi
Full text linkIn the current technological development, the electric motor is the most popular in various industrial applications. Electric motors today have evolved very quickly and have a significant impact on the lives of the wider community. The use of environmentally friendly and efficient energy is one of the reasons why this motorbike has become a pioneer of technological advances, especially in the automotive world. This research focuses on conducting a comprehensive analytical study on one type of electric motor, namely synchronous because it is widely applied in various conditions today. The analysis was carried out using a computational method by applying the finite element as a method of solving the magnetic field case involving Maxwell\u27s equations and its impact on the torque generated in this synchronous motor. From the computation results, it is found that this synchronous motor does have a high torque when the magnetic field flux works constantly at 0.015 Wb. With an average torque generated by this synchronous motor of 1.5 kW
Karakteristik Kekerasan Lasan Titik Gesekan dan Pengadukan pada Paduan Aluminium 5052-H112
Full text linkIssues in friction stir spot welding focus mainly on the mechanical characteristic affected by its Hardness. This Hardness must be maintained by evenly temperature distribution in weld zones during welding. The process parameters are mainly responsible for the development of the hardness of the friction stir spot weld. This study presented the hardness evaluations on the friction stir spot weld via the Hardness-Vickers test and analysis of the temperature distribution in the weld zones via the finite element method. The workpiece samples used in this study were Aluminium alloy 5052-H112 with a thickness of 2 millimeters in the lap-shear mode based on 3 main parameters at low and high levels of parameters configuration. The results obtained via the Hardness-Vickers tests exhibited a value of 42-HV located in the middle of the spot-weld center using a low-level parameters configuration. This value increased to 64-HV around the vicinity of the keyhole. And then the value decreased to 53-HV outside the keyhole, about 6 millimeters from the spot-weld center. Using high-level parameter configuration, the Hardness-Vickers value increased to 61-HV in the middle of the spot-weld center. The value then increased to 76-HV in the vicinity of the keyhole. Furthermore, the value decreased at 60-HV outside the keyhole, which ca 6 millimeters away from the spot-weld center. The temperature distribution of the weld zones achieved 480 oC in the vicinity of the keyhole using the low-level parameter configuration. Slowly, the temperature declined to 380 oC at 6 mm away from the friction spot-weld center in the HAZ. Using the high-level parameters configuration, the temperature distribution reached 540 oC in SZ, and slowly reduced to 425 oC in HAZ. Based on the results, it was found that by using high-level parameters configuration the hardness of the friction stirs spot weld exhibited better Hardness-Vickers value and evenly temperature distribution in the weld zones.  
Analisis Perpindahan Panas pada Sirkulasi Air Penyulingan Nilam dengan Tangki Bervolume 150 Liter
Full text linkIndonesia is the world’s main exporter of patchouli plants (Pogostemon Cablin Benth). Patchouli plants produce essential oil by distillation; this essential oil has a constituent component called patchouli alcohol and is widely used in the aromatic industry. Therefore, a patchouli refining process is needed so that Indonesia’s patchouli can improve its quality in the eyes of the world. The purpose of this research is to observe the process of cooling hot patchouli steam into patchouli oil to optimize the current process. This study\u27s analytical method is a simulation approach with CFD software. 50 kg of dried patchouli leaves and stems will go through a combustion process and then be distilled in a 150 liter volume tank for 5 hours. During the distillation process, there is a heat transfer phenomenon called conduction and convection. The LMTD value was 327 K, the heat transfer rate was 103,39 W, the overall heat transfer was 223,45 W/m2K, the NTU value was 0,018, and the system\u27s effectiveness was 0.89% using LMTD and the -NTU method
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
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