Judul: Utilization of Palm Shell Activated Charcoal as an Adsorbent on Biodiesel Dyes.
Abstrak: Adsorpsi zat warna pada biodiesel menggunakan arang aktif dari cangkang kelapa sawit dikaji dalam penelitian ini. Arang diaktifkan secara fisik pada suhu 800 °C selama 1 jam. Pencirian arang aktif yang dilakukan meliputi kadar air, kadar abu, daya adsorpsi terhadap iodin, daya adsorpsi terhadap biru metilena, memberikan hasil yang cukup baik bila dibandingkan dengan SNI, dan topografi permukaan menggunakan mikroskop elektron payaran. Hasil penelitian menunjukkan arang aktif memberikan kondisi optimum pada bobot adsorben 0.5 g selama 45 menit dengan nilai kapasitas dan efisiensi adsorpsi berturut-turut sebesar 103.64 mg/g dan 20.80%. Konsentrasi zat warna biodiesel turun dari 10 000 ppm menjadi 7 919.72 ppm, sedangkan angka setana biodiesel meningkat sebesar 9.85% dari 51.2 menjadi 56.8. Adsorpsi cangkang sawit menunjukkan model isoterm Freundlich sehingga diasumsikan terjadi secara multilayer atau banyak lapisan.
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Judul: Pembuatan Arang Aktif Tempurung Kelapa Sawit Sebagai Adsorben Dalam Pemurnian Biodiesel
Abstrak: Palm shell is one of solid waste from palm oil industries. To increase the added value and to reduce solid waste palm shell can be converted as activated charcoal. Application of activated charcoal could be done for purification process of biodiesel. Production of activated charcoal could be made through carbonization process at temperature of 450oC for five hours. The charcoal was soaked for 24 hours with the activator agent such as phosphoric acid activated with concentration of 15% and charcoal which was not soaked with phosphoric acid. Both of the charcoals were activated at temperature of 800oC with the variation time of 60, 90, and 120 minutes. The best quality of activated charcoal was the activation charcoal which were not soaked and activation time. The best quality of activated charcoal was the activation charcoal which were not soaked and activation time for 120 minutes with yield value of 56.5%, water content of 2.45%, volatile matter of 10.66%, ash content of 6.83%, fix carbon of 82.51%, adsorptive capacity of iodine 878.31mg/g, adsorptive capacity of benzene of 20,14%, and pH of 9.42. Crystalinity of activated charcoal of 39.89 %. Activated charcoal had been the standard of Standar Nasional Indonesia (SNI) 06-3730-1995. The ability of the best activated charcoal would be applicated for purification of biodiesel. Adding 3% of activated charcoal was better for purification of biodiesel so that was earned acid value of 0.22 mg KOH/g, pureness of 65.43%, pH of biodiesel of 7.29.
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Judul: Approximation of the Median of Poisson Distribution Using the Relation of Poisson-Gamma Distribution
Abstrak: A major drawback of median is that median cannot usually be defined in closed form, even in the cases where their distribution functions are known. This study gives an approximation of the closed form for the median of the Poisson distribution by using the relation of Poisson-Gamma distribution. The approximation uses elementary techniques based on the monotonicity of certain sequences involving tail probabilities of the Poisson distribution and the Central Limit Theorem. Furthermore, a closed form expression for the mean absolute deviation 􀜧|􀜰􀰒 􀵆 􀜯􀝁􀝀􁈺􀜰􀰒􁈻| is also studied. The median is relevant because of the fact that it minimizes the mean absolute deviation of a Poisson random variable (􀜰􀰒􁈻 by considering median as central tendency.
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