1,720,973 research outputs found
Pengaruh Variasi Normalitas NaOH pada Aktivasi Basa-Fisik Zeolit Pelet Perekat terhadap Prestasi Sepeda Motor Bensin 4-Langkah
Full text link Natural zeolite is an alternative adsorbent. It needs firstly to be activated before using it as absorbent in order to get zeolite with high adsorption capacity. Previously, the use of pelletized zeolite activated by NaOH-physic and KOH-physic with varied normalities was only performed in a diesel engine to observe the engine performance.In this study there were two kinds of activation, that is chemical activation with NaOH activator variation on the normality of 0.25 N, 0.5 N, 0.75 N, and 1.0 N and physical activation with using a temperature of 220 °C for 2 hours. All are made in the form of adhesive zeolite pellets with a diameter of 10 mm and a thickness of 3 mm. From the test results and analysis showed that the use of chemically activated zeolite can improve the performance of 4-stroke petrol engine when compared without using zeolite. The best performance in this experiment obtained at the normality of 0,75 N. At road test, the pelletized zeolite can reduce the fuel consumption 23, 15 %, and 16,51 % at stationary test, and increase acceleration by 14,77 %.Keywords: zeolite adsorbent, variation of normality, activator of NaO
Pengaruh Variasi Jenis Aktivator Asam dan Nilai Normalitas Pada Aktivasi Zeolit Pelet Perekat Terhadap Prestasi Mesin Motor Diesel 4-Langkah
Full text linkThe energy crisis and air pollution can be coped with using very abundant Natural Zeolites available in Indonesia, particularly in Lampung. Herry Wardono has applied the zeolite on petrol and diesel engines. In this applications, Lampung's natural zeolites can significantly save fuel consumption and reduce exhaust emissions of the engines. The best results occurred in the use of chemical-physical activated zeolite. All this time, chemical activator (acidic activator) used was H2SO4 0.2 N, and other normalities of this acid have not been tested, as well as other types of acidic activator. In this research, acidic activators used were H2SO4 and HCl which has a normality of 0.1 N, 0.2 N, 0.3 N and 0.5 N each. The amount of adhesive pelletized zeolite used was also variated, i.e 50, 100, and 150 grams. The results showed that the adhesive pelletized zeolite activated by HCl dominate the best results, with fuel consumption savings of 8.6472% and 10.3058% in the use of 100 and 150 grams of the zeolite. Meanwhile, the highest fuel consumption savings obtained in the use of adhesive pelletized zeolite activated by H2SO4 were 6.2992% and 7.8847%.Keywords: zeolit pelet perekat, oxygen- rich combustion, prestasi mesin diese
Kemampuan Bentonit Pelet Tekan Teraktivasi Fisik Sebagai Pengganti Zeolit Dalam Menghemat Konsumsi Bahan Bakar Motor Diesel 4-Langkah
Full text linkPropinsi Lampung merupakan salah satu produsen zeolit terbaik dan terbesar di Indonesia.Herry Wardono telah membuktikan kemampuan zeolit Lampung dalam meningkatkan prestasi motor bakar.Disamping zeolit, potensi bahan tambang bentonit juga tersedia melimpah di Propinsi Lampung.Bentonit memiliki bentuk senyawa yang tidak jauh berbeda dengan zeolit, dan kesamaan sifat dengan zeolit yaitu dapat mengadsorbsi uap air dan nitrogen. Bentonit pellet tekan teraktivasi fisik diletakkan pada saringan udara motor diesel 4-langkah. Konsentrasi bentonit dalam bentonit pelet diaktivasi fisik adalah 70, 75, dan 80%, dan berat bentonit divariasi sebesar 25, 50, dan 100 gram.Hasil pengujian menunjukkan bahwa terjadi penurunan (penghematan) konsumsi bahan bakar spesifik engkol. Persentase penghematan konsumsi bahan bakar tertinggi terjadi pada konsentrasi 70 % yaitu sebesar 8,1331 % pada putaran mesin 3500 rpm dengan berat 25 gram dan diameter 15 mm, dan pada konsentrasi 80 % sebesar 9,4275 % pada putaran mesin 3000 rpm dengan berat 100 gram dan diameter 10 mm. Namun, secara rata-rata persentase penghematan konsumsi bahan bakar tertinggi terjadi pada konsentrasi 70 %, yaitu sebesar 3,6031%. \ud
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Kata Kunci: bentonit pelet tekan, adsorpsi nitrogen, prestasi mesin diesel.\u
KEMAMPUAN BENTONIT PELET TEKAN TERAKTIVASI FISIK SEBAGAI PENGGANTI ZEOLIT DALAM MENGHEMAT KONSUMSI BAHAN BAKAR MOTOR DIESEL 4-LANGKAH
Full text linkPropinsi Lampung merupakan salah satu produsen zeolit terbaik dan terbesar di Indonesia. Herry Wardono telah membuktikan kemampuan zeolit Lampung dalam meningkatkan prestasi motor bakar. Disamping zeolit, potensi bahan tambang bentonit juga tersedia melimpah di Propinsi Lampung. Bentonit memiliki bentuk senyawa yang tidak jauh berbeda dengan zeolit, dan kesamaan sifat dengan zeolit yaitu dapat mengadsorbsi uap air dan nitrogen. Bentonit pellet tekan teraktivasi fisik diletakkan pada saringan udara motor diesel 4-langkah. Konsentrasi bentonit dalam bentonit pelet diaktivasi fisik adalah 70, 75, dan 80%, dan berat bentonit divariasi sebesar 25, 50, dan 100 gram. Hasil pengujian menunjukkan bahwa terjadi penurunan (penghematan) konsumsi bahan bakar spesifik engkol. Persentase penghematan konsumsi bahan bakar tertinggi terjadi pada konsentrasi 70 % yaitu sebesar 8,1331 % pada putaran mesin 3500 rpm dengan berat 25 gram dan diameter 15 mm, dan pada konsentrasi 80 % sebesar 9,4275 % pada putaran mesin 3000 rpm dengan berat 100 gram dan diameter 10 mm. Namun, secara rata-rata persentase penghematan konsumsi bahan bakar tertinggi terjadi pada konsentrasi 70 %, yaitu sebesar 3,6031%.Kata Kunci: bentonit pelet tekan, adsorpsi nitrogen, prestasi mesin diesel
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
PENGARUH VARIASI JENIS AIR DAN KONDISI AKTIVASI DARI ADSORBEN FLY ASH BATU BARA TERHADAP PRESTASI MESIN DAN KANDUNGAN EMISI GAS BUANG SEPEDA MOTOR KARBURATOR 4-LANGKAH
Full text linkThe activated fly ash of coal as adsorbent pellets can be used to save fuel consumption. This research is done with some testing that is the runs test (road test and acceleration), stationary and emission testing. Fly Ash pellets packed in a frame and put on the air filter absolute revo 110 cc motorcycle. So before the air filter into the vehicle, it wil be contact with the pellets Fly Ash first. In this study, the most efficient types of water used is H12 Z20 and the best conditions was on the temperature 150o C and activation time of 1 hour with fuel savings in road test reached 12.69%, and fuel economy at a stationary test up to 22.65% and the reduction of travel time ( 0-80 km/h ) of 6.86%. Fly Ash pellets are able to reduce the levels of CO by 76,92 %, 19,57 % for HC levels and raise their levels of CO by 4,36 %.Keywords : Fly ash adsorbent pellets, engine performance, exhaust gas emission
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
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