1,720,962 research outputs found
ANALISIS TOTAL ANTOSIANIN DARI DAUN BAYAM MERAH (Alternanthera Amoena Voss.) BERDASARKAN PENGARUH PENAMBAHAN JENIS ASAM
Get PDFBayam Merah (Alternanthera Amoena Voss.) merupakan salah satu jenis tanaman yang mengandung zat warna antosianin. Tujuan penelitian ini untuk mengetahui total antosianin dari daun bayam merah (Alternanthera Amoena Voss.) terhadap pengaruh penggunaan jenis asam. Daun bayam merah yang segar diekstraksi dengan pelarut etanol/HCl 0,1 M (A), etanol/asam sitrat 3% (B), etanol/CH3COOH 25 % (v/v) (C) dan pelarut etanol (D), ekstraksi dilakukan dengan metode maserasi dalam keadaan gelap selama 24 jam. Kemudian diidentifikasi dengan spektroskopi UV-Vis dan KLT. Dari analisis data spektroskopi didapatkan jenis antosianin yang terdapat pada bayam merah yaitu sianidin yang menyerap pada λ maksimum sebesar 290 nm (UV) dan 536 (tampak) yang sesuai dengan literatur. Kadar total antosianin ekstrak A, B, C, dan D berturut-turut 132,76 mg/L ; 121,56 mg/L ; 107,21 mg/L ; 76,98 mg/L. Berdasarkan hasil Uji KL
Pengaruh Waktu, dan Dosis Adsorben Terhadap Penghilangan Ion Fe dalam Air Sumur Menggunakan Zeolit Alam Teraktifasi secara Kolom Adsorbsi
Get PDFTelah dilakukan penelitian tentang Pengaruh Waktu, dan Dosis Adsorben Terhadap Penghilangan Ion Fe dalam Air Sumur Menggunakan Zeolit Alam Teraktivasi.Penelitian ini memiliki tujuan untuk menghilangkan ion Fe yang terkandung dalam air sumur. Kolom yang digunakan menggunakan kolom kaca dengan ukuran panjang 15 cm, diameter 1 cm secara batch dengan laju alir 1,5 mL/menit. Waktu adsorbsi dilakukan dengan variasi 15 menit; 30 menit; 45 menit dan 60 menit, sedangkan variasi adsorben yang digunakan yaitu : 0,5 g ; 1,0 g; 1,5 g; 2,0 g. Dari hasil penelitian diperoleh semakin lama waktu ,bobot adsorben maka semakin meningkat pula kapasitas adsorbsi. Efisiensi penyerapan tertinggi berdasarkan waktu kontak adsorben yaitu pada menit 60 menit sebesar 99,04 %., sedangkan efisiensi adsorbsi optimum berdasarkan bobot adsorben yaitu 2,0 gram dengan nilai efisiensi adsorbsi sebesar 98,01%
PENGARUH PENAMBAHAN ASAM TERHADAP TOTAL ANTOSIANIN DARI BUAH BIT (BETA VULGARIS)
Get PDFBuah bit merupakan tanaman salah satu family dari Beta vulgaris. Penelitian ini bertujuan untuk mengetahui efektifitas pelarut dalam mengekstraksi pigmen antosianin. Pelarut yang digunakan terdiri dari 3 variasi yaitu 1) akuades, 2) akuades yang diasamkan dengan HCl dan 3) akuades yang diasamkan dengan asam asetat. Proses ekstraksi dilakukan dengan metode maserasi dalam keadaan gelap
PENENTUAN ANTOSIANIN DARI DAUN BAYAM MERAH (Alternatera amoena Voss) SERTA APLIKASINYA SEBAGAI PEWARNA MINUMAN
Get PDFKEMAMPUAN TANDAN KOSONG KELAPA SAWIT SEBAGAI ADSORBEN UNTUK MEREGENERASI MINYAK JELANTAH
Get PDFPada penelitian ini dipelajari kemampuan tandan kosong kelapa sawit sebagai adsorben, untuk menurunkan bilangan peroksida (PV), dan warna gelap minyak goreng bekas. Pengolahan dengan adsorben ini diharapkan dapat meningkatkan kualitas minyak jelantah sehingga umur pemakaian minyak goreng dapat diperpanjang. Adsorben dari tandan kosong kelapa sawit disiapkan dibersihkan dan digiling, dilakukan proses aktivasi menggunakan asam phosphat (H3PO4). Selanjutnya serbuk dipanaskan dalam furnace pada temperatur 170oC selama satu jam, kemudian temperatur dinaikkan 500oC selama satu jam. Proses adsorpsi dilakukan dengan mengkontakkkan minyak goreng bekas dan adsorben pada suhu 7
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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