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PraRancangan Pabrik FUEL GRADE ETHANOL DARI BATANG SORGUM Kapasitas 50.000 ton/tahun
Full text linkFuel Grade Ethanol (FGE) merupakan etanol yang dapat digunakan sebagai
bahan bakar, memiliki kadar 99,5% dengan kadar air maksimal 0,05%. Selain
dapat dimanfaatkan sebagai bahan bakar alternatif, FGE juga berfungsi sebagai
peningkat angka oktan gasoline (octane booster) dengan dicampurkan ke dalam
gasoline. Dilihat dari bahan bakunya maka FGE ini termasuk renewable energy,
sehingga prospek pengembangannya akan semakin diminati.
Pabrik FGE dirancang dengan kapasitas 50.000 ton/tahun. Berdasarkan
aspek ketersediaan bahan baku lokasi pabrik didirikan di Demak, Jawa Tengah
menggunakan bahan baku berupa batang sorgum yang diperoleh dari petani di
beberapa kabupaten Jawa Tengah. Perusahaan akan didirikan dengan badan
hukum Perseroan Terbatas (PT), dengan jumlah karyawan 430 orang. Pabrik
beroperasi selama 330 hari dalam setahun, dengan proses produksi selama 24
jam/hari.
Bahan baku berupa batang sorgum digiling untuk mengambil nira dari
baggase, kemudian nira dilewatkan screener. Komposisi keluar screener terdiri
dari, sukrosa, glukosa, air, asam akonitat, pati dan kotoran. Untuk menghilangkan
asam akonitat dan kotoran maka dilanjutkan proses defikasi-sulfitasi. Defikasi
yaitu penambahan susu kapur untuk membentuk kalsium akonitat dan flok-flok.
Flok-flok akan diendapkan dengan penambahan gas SO
2
(sulfitasi) sehingga
terbentuk CaSO
3
yang akan menjatuhi flok-flok dan mengendap secara gravity.
Hasil dari proses diatas berupa larutan nira encer 14º brix yang kemudian akan
dipekatkan hingga 65º brix di Evaporator-01. Selanjutnya nira dan enzim
invertase (katalis) diumpankan ke Reaktor-01. Di Reaktor-01 terjadi reaksi
hidrolisis, yaitu memecah sukrosa menjadi glukosa. Kemudian dari Reaktor-01
langsung diumpankan ke Reaktor-02. Di Reaktor-02 terjadi reaksi fermentasi,
yaitu mengubah glukosa menjadi etanol dengan bantuan enzim zymase sebagai
katalis. Dari Reaktor-02 etanol-air akan dipisahkan dari padatan menggunakan
Evaporator-02. Hasil atas berupa uap campuran biner etanol-air. Campuran biner
ini akan dimurnikan bertahap sampai 99,5% menggunakan Menara Distilasi dan
Membran pervaporasi, lalu etanol 99,5% dialirkan menuju tangki penyimpanan
sebagai produk dan siap untuk didistribusikan. Untuk menunjang proses produksi
dan berjalannya operasi pabrik, dibutuhkan unit penunjang untuk penyediaan air
sebanyak 48.608,03 l/jam, freon-22 27.121,50 kg/jam, bahan bakar boiler
38.344,71 kg/jam, bahan bakar generator 231,54 kg/jam, udara tekan 39,6 m /jam,
steam 108.153,46 kg/jam dan kebutuhan listrik 2.140 kW.
Untuk mendirikan pabrik FGE diperlukan modal investasi sebesar
US$ 23.392.557 + Rp 397.752.234.927. dengan nilai bunga (DCF) sebesar
18,10%, harga pokok Rp 5.049/liter dengan harga jual Rp 6.591/liter. Indikator
ekonomi pabrik menunjukkan nilai ROI sebelum pajak sebesar 22,51% dan ROI
sesudah pajak sebesar 15,76%. Nilai POT sebelum pajak adalah 3,43 tahun dan
POT sesudah pajak adalah 4,46 tahun. BEP sebesar 40,51% kapasitas produksi
dan SDP sebesar 13,82% kapasitas produksi. Berdasarkan data indikasi ekonomi
tersebut, maka pabrik Fuel Grade Ethanol layak untuk dikaji lebih lanju
EFEKTIFITAS METODE STUDENTS TEAMS LEARNING DALAM MENINGKATKAN HASIL BELAJAR MATEMATIKA SISWA KELAS VIII B SMP NEGERI 10 PALOPO
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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
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
Adsorpsi Air dari Campuran Uap Etanol-Air dengan Zeolit Sintetis 4A dalam Packed Bed dalam Rangka Produksi Fuel Grade Ethanol
Full text linkEthanol can be used as fuel if it has a purity of 99.5%, while ethanol distillation will stop at its azeotrop point, ie at 95.6%. Adsorption of molecular sieve is one of the methods to obtain ethanol with level above the azeotropic point. Adsorbent that serves as molecular sieve is synthetic zeolite 4A. The adsorbent has a pore diameter of 3.9 Ǻ, then water and ethanol each has a molecular diameter of 2.75 Ǻ and 4.4 Ǻ. Hence the adsorbent is selective against the ethanol-water mixture. The purpose of this research is to obtain ethanol above its azeotropic point and to study the relationship between the influence of flow rate (Vz) and temperature (T) to changes in the number of mass transfer coefficient (kc), radial diffusivity (Der) and henry constants (H') which can be used as parameters in the design of adsorption tools on a commercial scale.This experiment was conducting by weighing zeolite 4A as much as 100 grams, then compiled and measured the height on packed bed column adsorbent. The heating regulator is switched on and set to a constant temperature of 80, 85, 90, 95 and 100 0C. Ethanol 95.61% with 250 ml volume is put into three-neck flask, then heat to evaporate. Turn on the cooling back and adjust the amount of formed vapor rate by adjusting the faucet opening and the degree of voltage in the heating mantle. The magnitude of the vapor flow rate is set at 2, 4 and 6 liters / minute. The products is accomodated and samples were taken every minute to analyze the ethanol content.This adsorption process gives the highest yield of ethanol with 99.40% content. The steam flow rate of 2 lpm and the temperature of 800C is the optimum combination in this research because much of the water vapor adsorbed on the 4A zeolite grain is 7.93 grams. The numerical calculation provides the result that the value of Der in this experiment is 1.59.10-3 cm2 / men, and the relation of kc are the function of reynolds and H' the function of temperature are as follows: kc = 7,95.10^-3.(Re)^0,1639 and H' = 4,47.10^-3.exp(2565,26/T) ABSTRAKEtanol dapat digunakan sebagai bahan bakar jika memiliki kemurnian 99,5%, sedangkan dislitasi etanol akan terhenti pada titik azeotropnya, yaitu pada 95,6%. Adsorpsi molecular sieve adalah salah satu metode untuk memperoleh etanol dengan kadar diatas titik azeotrop. Adsorbent yang berfungsi sebagai molecular sieve adalah zeolit sintetis 4A. Adsorbent ini memiliki diameter pori sebesar 3,9 Ǻ, lalu air dan etanol masing-masing memiliki diameter molekul 2,75 Ǻ dan 4,4 Ǻ. Maka dari itu adsorbent bersifat selektif terhadap campuran etanol-air. Penelitian ini bertujuan untuk memperoleh etanol diatas titik azeotropnya serta mempelajari hubungan pengaruh laju alir (vz) dan suhu (T) terhadap perubahan harga koefisien transfer massa (kc), difusivitas radial (Der) dan konstanta henry (H’) yang bisa digunakan sebagai parameter dalam perancangan alat adsorpsi pada skala komersial. Percobaan ini dilakukan dengan cara menimbang zeolit 4A sebanyak 100 gram, lalu disusun dan diukur tingginya pada packed bed columnadsorbent. Regulator pemanas dinyalakan dan diatur suhunya sampai konstan pada 80, 85, 90, 95 dan 1000C. Etanol 95,61% dengan volum 250 ml dimasukkan ke labu leher tiga, lalu dipanaskan sampai menguap. Pendingin balik dinyalakan dan diatur besarnya laju uap yang terbentuk dengan mengatur bukaan kran dan derajat voltase pada heating mantle. Besarnya laju aliran uap diatur pada 2, 4 dan 6 liter/menit. Produk ditampung dan diambil tiap menit sebagai sampel untuk dianalisis kadar etanolnya. Proses adsorpsi ini memberikan hasil tertinggi berupa etanol dengan kadar 99,40%. Laju alir uap 2 lpm dan suhu 800C adalah kombinasi yang optimal dalam penelitian ini karena banyak uap air yang teradsorpsi pada butir zeolit 4A yaitu 7,93 gram. Perhitungan secara numeris memberikan hasil bahwa nilai Der pada percobaan ini adalah 1,59.10-3 cm2/men, serta hubungan kc fungsi reynolds dan H’ fungsi suhu berturut-turut adalah sebagai berikut:kc=7,95.10-3..vz.D0,1639dan H'=4,47.10-3.e2565,26T
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
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
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