1,720,962 research outputs found
Analysis of thickness and colour changes of medium carbon steel subjected to nickel electroplating
No full textThe research-based learning development model as a foundation in generating research ideas
No full textAnalisis Variasi Holding Time Peleburan Terhadap Kekuatan Impak, Cacat Makro, dan Struktur Mikro pada Pengecoran Logam Al-Si
No full textABSTRAK Dika, Johan Wayan. 2016. Analisis Variasi Holding Time Peleburan Terhadap Kekuatan Impak, Cacat Makro, dan Struktur Mikro pada Pengecoran Logam Al-Si. Skripsi, Jurusan Teknik Mesin, Fakultas Teknik, Universitas Negeri Malang. Pembimbing: (I) Drs. H Putut Murdanto, S.T., M.T. (II) Drs. Imam Sudjono, M.T. Kata Kunci : Al Si, Holding Time Peleburan, Kekuatan Impak, Cacat Makro, Struktur Mikro Aluminium murni merupakan logam yang mempunyai sifat ringan, tahan korosi, kekuatan yang dapat ditingkatkan dan mampu cor yang baik. Dari beberapa penelitian menjelaskan bahwa cara untuk meningkatkan sifat mekanis dari aluminium, diantaranya ialah dengan menambahkan unsur paduan seperti tembaga, silisium, magnesium, mangan, dan nikel serta memberikan holding time pada peleburan yang meningkatkan nilai kekerasan yang sifatnya berbanding terbalik dengan ketangguhan. Untuk itu, perlu dilakukan analisis holding time pada peleburan terhadap kekuatan impak, cacat makro, dan mikro struktur pada hasil coran Al-Si, dengan variasi holding time 0 menit, 15 menit, 25 menit, dan 35 menit. Tujuan dari penelitian ini adalah (1). Mengetahui harga kekuatan impak akibat holding time pada peleburan coran Al-Si; (2). Mengetahui bentuk cacat makro akibat holding time pada peleburan coran Al-Si; (3). Mengetahui bentuk struktur mikro akibat holding time pada peleburan coran Al-Si. Metode penelitian yang digunakan dalam penelitian ini adalah rancangan penelitian eksperimental dengan jenis pendekatan kuantitatif. Teknik analisis data yang digunakan dalam penelitian ini adalah analisis deskriptif yang dilakukan dengan cara merangkum hasil penelitian berdasarkan pengamatan dan uji laboratorium yang telah dilakukan. Data yang berupa nilai dan kemudian diolah dengan pengambilan nilai rerata dan ditampilkan dalam bentuk tabel dan diagram sehingga mudah untuk dibaca. Pengujian ketangguhan menggunakan mesin uji takik dengan metode Charpy dan standart ASTM E23. Pengamatan cacat makro diamati dengan foto makro dan untuk struktur mikro diamati dengan foto mikro. Harga impak coran Al-Si akibat holding time peleburan dengan variasi waktu 0 menit, 15 menit, 25 menit, dan 35 menit, didapatkan harga impak yang menurun dari 0,335 joule/mm2 ke 0,247 joule/mm2 dan meningkat hingga 0,277 joule/mm2, hal ini terjadi akibat cacat porositas hasil coran Al-Si. Patahan getas terjadi pada semua spesimen. Ukuran butir struktur mikro semakin kecil seiring dengan lamanya holding time. Pada penelitian ini, menegaskan bahwa harga impak mempunyai hubungan yang terbalik dengan cacat porositas, semakin tinggi harga impak semakin rendah cacat porositasnya, dan semakin rendah harga impak semakin tinggi cacat porositasnya. Berdasarkan pengamatan struktur mikro pada coran Al-Si akibat holding time peleburan dengan variasi waktu 0 menit, 15 menit, 25 menit, dan 35 menit didapatkan ukuran butir yang semakin kecil. Semakin lama holding time, maka ukuran dari Al-Si semakin kecil
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
Material oksida sebagi penguat panduan alumunium silikon / Poppy Puspitasari, Johan Wayan Dika
No full textVariations 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
- …
