1,720,958 research outputs found
Pengaruh Perubahan Kecepatan Pemakanan Terhadap Kekasaran Permukaan Pada Proses Pembubutan
Get PDF This research done to know existence of transformation influence of feeding speed at turning process to surface roughness of work substance. Specimen material is ST 37 with Ø 30, 40, 50 and 70 mm, with transformation of feeding speed 0,05, 0,069, 0,088, 0,125 and 0,17(mm/rev), depth of feed 0,2 mm, and speed of revolution of engine 950 rpm. Then the several assaying of surface roughness level of the specimen and calculation statistic by using one way variant analytical method based on data result of assaying. Result of research indicates that existence of influence significant to surface roughness value caused by transformation of feeding speed at specimen turning process Ø 30, 40, 50 and 70 mm, ST 37 material with depth of feed 0,25 mm and revolution of engine 950 rpm. Average of smallest roughness value is at Ø 30 mm yielding best surface roughness. This thing indicates that feeding speed and substance diameter lathed influential to surface roughness value
Pembuatan model alat pembuang panas untuk air pendingin alat praktikum heat exchanger merk PA Hilton seri H101 di laboratorium teknik mesin
Get PDFHeat Exhanger Service Unit H101/08490 P.A Hilton Ltd that use for heat transfer experiment has a weakness because the water flow from the unit after taking heat will directly enter the storage tank, still have a high temperature ( >33oC ). The use of practicum equipment for a experiment with a long enough duration will cause the cooling water are used have a high temperature and be ineffective for the heat exchanger cooling process. The purpose of making a Cooling Tower Type Heat Dissipator Model for Heat Exhanger Service Unit H101/08490 P.A Hilton Ltd so that the cooling water used to carry out the practicum will be maintained at a temperature of 28oC-33oC. Maintaining the stability of the cooling water temperature is expected to produce data that does not vary too much and can be done in a fairly long data collection range. The results of the performance and effectiveness test of cooling tower cooling show that the temperature increase is only 4oC for 3 hours of testing and the cooling effectiveness increases and is relatively constant during the test time. This shows that the cooling system with a cooling tower can be used as a supporting medium for heat exchanger practicum in the Mechanical Engineering department
Rancang Bangun Model Turbin Pelton Mini Sebagai Media Simulasi/Praktikum Mata Kuliah Konversi Energi Dan Mekanika Fluida
Get PDFThis Research is conducted in Pontianak state Polytechnic using test-drive method based on literature. The step are scheme/ turbine design, making and repairing in order to get a better pelton turbine. The main objective of this research is to provide facility for energy conversion and fluid mechanism practice which is limited in Mechanical Engineering Department so that it is hoped that it will contribute positive effects on students ability in that field. The construction and specification of pelton turbine model resulted of this research as follows; ( 1) Type Pump: Jet propulsion Pump, with the energy input 500 Watt, head pump 55 m, and debit 30 L / minute. ( 2) Generator energy 500 VA and Rpm 1500 rpm, 50 Hz. ( 3) Runner specification: The sum of buckets / sudu is 8 ( single and double), runner diameter 17 cm, out side diameter 44 cm, the width of bucket 6 cm, the length is 14 cm, and pitch pelton wheel diameter is 30 cm. ( 4) Nozzle diameter is 20 mm. The result of research on this pelton turbine model shows of water kinetic energy into electrical energy resulted by pelton turbine, and the bucket type design as well as the sum influence the rpm and voltage gained
Pengaruh perubahan geometri nosel pada aliran dua fase terhadap kinerja liquid-gas ejector
Get PDFLiquid-gas ejector is an energy conversion device capable of flowing air fluid by utilizing water fluid based on the pressure difference between the two fluids without using moving parts. This study aims to determine the effect of changes in nozzle geometry on two-phase flow on the performance of the liquid-gas ejector. The method used is by conducting an experiment whose stages include: determining the nozzle geometry parameter, primary flow rate, and secondary flow rate. Then carry out tests on the installation of liquid-gas ejectors and collect data. The test is done by alternating the nozzle geometry, primary flow rate, and secondary flow rate. Next, analyze the data that has been collected to get the efficiency or performance of the liquid-gas ejector from changes in the nozzle geometry. The results showed that increasing the nozzle geometry tends to cause a decrease in the efficiency and coefficient of the nozzle. The maximum efficiency produced by each nozzle with a geometry of 0.57; 0.64; 0.71; 0.79 and 0.86 respectively were 24.33%, 23.43%, 8.19%, 16.21%, and 7.96%. While the nozzle coefficients are 0.94, respectively; 0.81; 0.59; 071; and 0.59
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
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