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Studi numerik distribusi temperatur dan kecepatan udara pada unit filling lithos PT. Pertamina LOBP Gresik
Get PDFMerencanakan sistem pengkondisian udara yang tidak hanya mengatasi kenyamanan termal yang terjadi, tetapi juga mengurangi penggunaan energi adalah sesuatu yang sangat diperlukan pada saat ini. Makalah ini menggambarkan penggunaan permodelan CFD untuk menganalisis kenyamanan termal yang terjadi di area filling lithos PT. Pertamina LOBP PUG di Gresik, dimana luasnya mencapai tiga ribu meter persegi, kebutuhan akan analisis ini disebabkan adanya kondisi yang dirasa kurang nyaman dari para pekerja, dimana temperatur ruangan yang tinggi melebihi kriteria nyaman yang ditentukan oleh ASHRAE. Untuk mendinginkan secara keseluruhan area filling lithos ini dibutuhkan kapasitas pendinginan sekitar 0,3 MW dan ini tentunya tidak efektif, karena beban pendinginan utama yang harus diatasi adalah beban panas dari para pekerja itu sendiri. Oleh karena itu diperlukan perancangan sistem pengkondisian udara yang lebih efisien. Penelitian serupa pernah dilakukan pada line 1 area ini, namun kecepatan udara yang dihasilkan diffuser pendinginan belum memenuhi kriteria nyaman yang ditetapkan oleh ASHRAE. Untuk itu penelitian ini dilakukan untuk menganalisis pengaruh kecepatan dan ketinggian inlet udara suplai diffuser terhadap kenyamanan para pekerja.
Simulasi dilakukan secara 3-Dimensional dengan menggunakan software FLUENT 6.3.26 dan GAMBIT 2.4.6. Area yang akan disimulasikan adalah line 2 dari area filling lithos, yang berukuran 10,3m x 40m x 13,5m, dengan pengkondisian udara berupa 4 buah ventilator dan 2 unit blower fan. Udara diasumsikan sebagai incompressible gas ideal, aliran steady, model turbulensi yang digunakan adalah standard k-ε, kriteria konvergen untuk energy 10-6, dan untuk selain energy 10-4, pressure- velocity coupling menggunakan algoritma SIMPLE dan second order upwind discretization. Simulasi dilakukan dengan skema existing dan skema perencanaan dimana akan dilakukan variasi kecepatan inlet udara suplai diffuser 1,5 m/s, 2 m/s, dan 2,5 m/s, dan variasi ketinggian diffuser 4,2 m.
Melalui simulasi skema existing diperoleh hasil bahwa temperature pada occupant zone berkisar antara 34–36 ºC nilai ini melebihi kriteria temperature yang nyaman menurut ASHRAE. Sebaliknya pada skema existing, dengan adanya penambahan diffuser menunjukkan hasil temperature yang lebih baik, berkisar antara 24-26 ºC dan kecepatan inlet diffuser sebesar 2 m/s menghasilkan kecepatan udara yang nyaman di sepanjang tubuh pekerja yaitu sekitar 0,13 – 0,22 m/s. Untuk kecepatan udara suplai sebesar 2,5 m/s, laju aliran massa yang harus disuplai oleh AHU sekitar 15 kg/s, sehingga kapasitas pendinginan yang dibutuhkan sebesar 0,231 MW. Dibandingkan dengan ketika mendinginkan seluruh ruangan dimana dibutuhkan kapasitas pendinginan 0,3 MW maka metode ini memiliki efisiensi sebesar 30 %. Dari simulasi ini kita juga mengetahui bahwa semakin tinggi kecepatan udara pada sisi para pekerja, Re semakin meningkat akibatnya Nu juga meningkat. Dengan meningkatnya Nu maka heat transfer koeffisien juga akan semakin meningkat
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Planning for air conditioning systems which not only overcome the thermal comfort issues but also reduces energy use, is something that is needed at this time. This paper describes the use of CFD modeling to analyze the thermal comfort in the filling area lithos PT. Pertamina LOBP PUG in Gresik, where the extent of three thousand square meters, the need for this analysis due to the uncomfortable conditions felt by workers, where the room temperature exceeding the comfortable criteria specified by ASHRAE. For cooling the whole room, needed a cooling capacity of 0.3 MW and is very inefficiently, because the main cooling load that must be overcome is the heat load of the workers themselves. Therefore, it is necessary to design air conditioning systems more efficient. Similar studies have been done in line 1 of this area, but the speed of the diffuser cooling air generated cozy yet meet the criteria set by ASHRAE. Therefore this study was conducted to analyze the effect of the speed and altitude of the supply air inlet diffuser on the convenience of the workers.
Simulations conducted in 3-Dimensional using FLUENT software Gambit 6.3.26 and 2.4.6. The area to be simulated is the second line of filling area lithos, is sized 10,3m x 40m x 13,5m, with air conditioning in the form of 4 pieces ventilator and 2 unit blower fan. Air is assumed to be incompressible ideal gas, steady flow, turbulence models used is the standard k-ε, convergent criteria for energy 10-6and 10-4 for other energy, Pressure-velocity coupling using SIMPLE algorithm and second order upwind discretization.Simulations carried out by the existing schemes and the planning scheme which would perform variations of the supply air diffuser inlet velocity of 1.5 m / s, 2 m / s, and 2.5 m / s, and height of the diffuser is about 4.2 m
Through simulations showed that the existing schemes in the occupant zone temperature ranging between 34-36 ° C this value exceeds a comfortable temperature criteria specified by ASHRAE. In contrast to the existing scheme, planning scheme with the addition of a diffuser show a better result the temperatures range between 24-26 ° C and inlet diffuser speed of 2 m/s generate a comfortable air velocity along the worker's body at around 0.13 to 0.22 m/s. For the supply air speed of 2,5 m/s, the mass flow rate to be supplied by the AHU approximately 15 kg/s, so that the required cooling capacity of 0.231 MW. Compared with when cooling the whole room where the required cooling capacity of 0.3 MW, this method has an efficiency of 30 %. From these simulations we also know that the higher the speed of air on the side of the workers, increasing Re. As a results, Nu consequently also increases. By increasing Nu, the heat transfer coefficient will also increase
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
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
Author Under Sail The Imagination of Jack London, 1893-1902
No full textIn Author Under Sail, Jay Williams offers the first complete literary biography of Jack London as a professional writer engaged in the labor of writing. It examines the authorial imagination in London's work, the use of imagination in both his fiction and nonfiction, and the ways he defined imagination in the creative process in his business dealings with his publishers, editors, and agents. In this first volume of a two-volume biography, Williams traverses the years 1893 to 1902, from London's "Story of a Typhoon" to The People of the Abyss. The Jack London who emerges in the pages of Author Under Sail is a writer whose partnership with publishers, most notably his productive alliance with George Brett of Macmillan, was one of the most formative in American literary history. London pioneered many author models during the heyday of realism and naturalism, blurring the boundaries of these popular genres by focusing on absorption and theatricality and the representation of the seen and unseen. London created an impassioned, sincere, and extremely personal realism unlike that of other American writers of the time. Author Under Sail is a literary tour de force that reveals the full range of London as writer, creative citizen, and entrepreneur at the same time it sheds light on the maverick side of machine-age literature.Intro -- Title Page -- Copyright Page -- Dedication -- Contents -- Acknowledgments -- Introduction -- 1. Spirit Truth -- 2. From Absorption to Theatricality and Back Again -- 3. "I Will Build a New Present" -- 4. Sons as Authors -- 5. Fathers as Publishers -- 6. The Daughter as Author -- 7. Lovers as Authors -- 8. At Sea with the Family -- 9. Yellow News, Yellow Stories -- 10. The Return Home -- Notes -- Bibliography -- Index -- About Jay WilliamsIn Author Under Sail, Jay Williams offers the first complete literary biography of Jack London as a professional writer engaged in the labor of writing. It examines the authorial imagination in London's work, the use of imagination in both his fiction and nonfiction, and the ways he defined imagination in the creative process in his business dealings with his publishers, editors, and agents. In this first volume of a two-volume biography, Williams traverses the years 1893 to 1902, from London's "Story of a Typhoon" to The People of the Abyss. The Jack London who emerges in the pages of Author Under Sail is a writer whose partnership with publishers, most notably his productive alliance with George Brett of Macmillan, was one of the most formative in American literary history. London pioneered many author models during the heyday of realism and naturalism, blurring the boundaries of these popular genres by focusing on absorption and theatricality and the representation of the seen and unseen. London created an impassioned, sincere, and extremely personal realism unlike that of other American writers of the time. Author Under Sail is a literary tour de force that reveals the full range of London as writer, creative citizen, and entrepreneur at the same time it sheds light on the maverick side of machine-age literature.Description based on publisher supplied metadata and other sources.Electronic reproduction. Ann Arbor, Michigan : ProQuest Ebook Central, YYYY. Available via World Wide Web. Access may be limited to ProQuest Ebook Central affiliated libraries
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