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REDUKSI UKURAN ADSORBEN UNTUK MEMPERBESAR DIAMETER PORI DALAM UPAYA MENINGKATKAN EFISIENSI ADSORPSI MINYAK JELANTAH
Get PDFAbstrak: Pada penelitian yang telah dilakukan, dengan reduksi ukuran partikel hingga dibawah 2 μm dapat menghasilkan diameter pori yang masuk klasifikasi mesopori (2 "“ 50 nm). Uji kemampuan bentonit dan zeolit mesopori sebagai penjerap untuk meningkatkan kualitas minyak jelantah agar dapat digunakan kembali telah dilakukan dengan metode batch. Konsep batch dipilih karena tujuan penelitian adalah untuk mengetahui secara pasti parameter yang paling berpengaruh terhadap proses penjerapan dari variabel yang telah ditentukan. Penelitian dilakukan dengan variasi waktu 40, 55, dan 70 menit. Dosis penjerap sebagai variabel utama ditentukan 5, 15, dan 25%. Kecepatan pengadukan merupakan parameter yang berpengaruh terhadap tingkat kesempurnaan perlekatan ditentukan pada skala 3 dan 6 (225 dan 450 RPM). Dari hasil penelitian ditunjukkan bahwa kemampuan penjerapan bentonit dan zeolit mesopori dapat secara sempurna menghasilkan kualitas minyak goreng yang baik dari parameter warna, dimana kondisi optimum tercapai pada waktu proses 70 menit, dosis penjerap sebesar 25%, dan kecepatan pengadukan pada skala 6 (450 RPM) dengan nilai absorbansi sebesar 0,0117 Abs untuk bentonit (efisiensi 88,26%) dan 0,0100 Abs (efisiensi 89,97%) untuk zeolit dengan blanko minyak goreng baru sebesar 0,0000 Abs dan minyak jelantah sebesar 0,0997 Abs yang diukur pada panjang gelombang489,2 nm. Selain itu, hasil percobaan mendapatkan efisiensi penurunan nilai asam lemak bebas optimum mencapai 68,75% (bentonit) dan 62,50% (zeolit), jauh diatas hasil percobaan dengan penetralan basa dan menggunakan adsorben bentonit teraktivasi (31,28%) dan tanah diatomit (43,36%). Dari hasil tersebut maka dapat ditarik kesimpulan bahwa reduksi ukuran adsorben yang akan meningkatkan luas permukaan, volume pori, dan radius pori dapat meningkatkan efisiensi adsorpsi minyak jelantah pada parameter warna dan asam lemak bebas secara signifikan Kata kunci: bentonit, zeolit, mesopori, minyak jelantah, penjerapan Abstract : In the research result, by using particle size reduction to less than 2 μm, it can produce pore diameter were into mesoporous classification (2-50 nm). The ability testing for bentonite and zeolite mesopores as an adsorbent to improve the quality of used cooking oil so it can reuse, has been conducted by using a batch method. The batch concept selected because of research purpose was to determine the proper parameters that most influenced on the adsorbency process from predetermined variables. The research was conducted with the variation of time of 40, 55, and 70 minutes. The adsorbent dose as the main variable determined at 5, 15, and 25%. Stirring speed was a parameter affected the level of adhesion perfection that is determined on a scale of 3 and 6 (225 and 450 RPM). From the study results, indicated that the adsorbent ability of bentonite and zeolite mesopores could produce a good quality of cooking oil perfectly from color parameters, where the optimum condition reached during 70 minutes in process, adsorbent dose by 25%, and stirring speed on a scale of 6 (450 RPM) with the absorbency values of 0.0117 Abs(efficiency 88.26%) for bentonite and 0.0100 Abs (efficiency 89.97%) for zeolite, with a new form of cooking oil at 0.0000 Abs and used cooking oil at 0.0997 Abs. The form used was origin cooking oil before it used for frying, and its wavelength spectrophotometer used at 489.2 nm. In addition, the results of the experiment to get the efficiency of free fatty acid impairment optimum reach 68.75% (bentonite) and 62.50% (zeolite), well above the results of experiments with alkaline neutralization and use of activated bentonite adsorbent (31.28%) and soil diatomite (43.36%). From these results it can be concluded that the reduction in the size of the adsorbent will increase the surface area, pore volume and pore radius can enhance the adsorption efficiency of cooking oil on the parameters of color and free fatty acids significantly. Key words: bentonite, zeolites, mesoporous, used cooking oil, adsorption
RANCANGAN PENGOLAHAN LIMBAH PERTAMBANGAN EMAS RAKYAT DENGAN ECENG GONDOK (Eichhornia crassipes) DI BOLAANG MONGONDOW
No full textEmas yang merupakan komoditi penting dalam perekonomian dunia telah memicu pertumbuhan kegiatan pertambangan bijih emas, baik dalam skala besar maupun kecil. Pengolahan emas rakyat pada umumnya menggunakan merkuri, yang dikenal dengan proses amalgamasi. Pemakaian merkuri dapat mengakibatkan penurunan kualitas lingkungan. Penelitian di daerah Bolaang Mongondow menunjukkan kandungan merkuri di hulu sungai sebesar 0,024 ppm dan telah melebihi ambang batas yang diperbolehkan (0,002 ppm). Kandungan merkuri yang tinggi terdapat di sedimen kolam pengendapan No. 4, yaitu sebesar 3,01 ppm, jauh di atas ambang batas yang diperbolehkan (0,49 ppm). Berdasarkan hal tersebut, diperlukan suatu rancangan pengelolaan merkuri yang lebih baik untuk mengolah limbah cair dari proses amalgamasi dengan memanfaatkan teknologi sederhana yang didukung oleh kemampuan sumber daya alam setempat. Salah satu cara pengurangan kadar merkuri di badan perairan adalah dengan proses bioremediasi menggunakan tanaman air eceng gondok (Eichhornia crassipes) karena eceng gondok mudah didapat dan mempunyai kemampuan yang cukup baik dalam menyerap merkuri. Diharapkan dengan perancangan sederhana ini pencemaran air dapat dikurangi
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
POTENSI PEMANFAATAN LIMBAH PEMBAKARAN BATUBARA PLTU SEBAGAI MEDIA TANAM DALAM KEGIATAN REVEGETASI LAHAN BEKAS TAMBANG BATUBARA
No full textLahan bekas tambang batubara di Indonesia umumnya dicirikan dengan kondisi keseimbangan ekosistem permukaan tanah yang terganggu dan kualitas kesuburan tanah yang rendah. Oleh sebab itu, diperlukan upaya untuk mengatasi masalah tersebut di antaranya dengan memanfaatkan abu batubara sebagai bahan tambahan dalam media tanam untuk revegetasi lahan. Abu batubara diketahui mengandung unsur makro dan mikro yang berguna untuk meningkatkan kesuburan tanah dan pertumbuhan tanaman. Penelitian ini bertujuan untuk mengetahui pengaruh penggunaan abu batubara (campuran abu dasar dan abu terbang) sebagai media tanam terhadap pertumbuhan tanaman caisin (Brassica chinensis) dan LCC (Legume Cover Crops) jenis Centrosema pubescens serta akumulasi logam berat pada biomassa di kedua tanaman uji tersebut. Dilakukan analisis komposisi kimia abu batubara untuk mengetahui tingkat kesuburannya dan analisis pertumbuhan tanaman serta akumulasi logam berat pada biomassa di kedua tanaman uji tersebut. Dari hasil analisis, diketahui abu batubara PLTU Bukit Asam mengandung unsur-unsur yang berguna untuk menunjang pertum- buhan tanaman seperti Ca, S dan Mg. Penambahan abu batubara sebesar 10 % pada tahap ke-1, 2 dan 3 penanaman menghasilkan rata-rata berat basah caisin yang paling banyak di antara perlakuan lainnya masing-masing sebesar 15,9, 34,5 dan 23,8 gram. Penambahan abu batubara sebesar 17,5 % sampai dengan tahap penanaman ke-3 berpengaruh positif dengan menurunnya kandungan logam berat Cu, Zn, Pb dan Cd pada tanaman caisin masing-masing sebesar 40, 60, 100 dan 50%. Sedangkan untuk kandungan logam Cr dan As cenderung stabil pada setiap tahap penanaman. Pada tanaman Centrosema pubescens, penambahan abu batubara 5 % menghasilkan rata-rata biomassa yang paling banyak sebesar 27,1 gram. Penambahan abu batubara pada tanaman Centrosema pubescens menurunkan kandungan logam berat Pb dan Zn masing-masing sebesar 34,5 dan 25,3%, namun menaikkan kandungan logam Cu dan Cd masing-masing sebesar 41,7 dan 50%
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
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