Judul: Penjernihan nira tebu menggunakan membran ultrafiltrasi dengan sistem aliran silang
Abstrak: Membrane ultrafiltration is one alternative technology to produce a high quality cane sugar with reasonable cost, because its ability to produce a brighter color and lower impurities as well as sulphur free of product. This technology can reduce process steps, chemical and energy demand, so that the production cost is potentially reduced significantly. This research work was aimed to study the performance of various membrane filtrations in the application for clarifying sugar cane juice, covering the achievable flux, membrane rejection against impurities, and quality of the filtered juice. The experiments were conducted according to the principle of cross flow using three different transmembrane pressures of 0.7, 1.4, and 2.1 bar and cross flow rate of 0.42 m/s. Various membranes were studied in this experiments both commercial ultrafiltration membrane and ultrafiltration membrane prepared in our laboratory. Sugar cane juice before and after clarification were characterized by measuring the parameters of brix, sucrose concentration, solution color, clarity, and pH. The polisulfone membrane, which was prepared in our laboratory, produced fluxes in the range of 25-30 L/m2.h at the transmembrane pressures of 0.7-2.1 bar. The membranes increased clarity of the juice from app. 10 to 60% of transmition and reduced color up to 80-90%, comparable with the results of the commercial ultrafiltration membrane.
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Judul: Kajian Proses Pernumian dan Pemekatan Larutan Raw Sugar dengan Menggunakan Teknologi Membran
Abstrak: Proses pemurnian dan pemekatan larutan raw sugar mempengaruhi kualitas gula yang dihasilkan. Dalam penelitian ini dipeiajari dternatif proses pemurnian dm pemekatan larutan raw sugar dengan menggunakan teknologi rnembran. Membran yang digunakan untuk proses pernumian adalah membran ultiafdtrasi dengan Molecular Weight Cut Off W C O ) 10000 Da serta membran nanofiltrasi dengan MWCO 600 Da. Proses ini ktujuan untuk mengamati fluks dan karakteristik hasil pernumian s e w dasar pemilihan penggunaan membran uhddtcasi atau nanofiltrasi serta menentukan kandisi optimum tekanan membran ultrafdtrasi dm nanofihsi. Membran yang digunakan untuk proses pernekatan adalah rnembran reverse osmosis tip 4820ULP dengan rejeksi NaCl 98.5%. Pada proses pemekatm dipelajati kuahtas hasil pemekatan larutan raw sugar, kinerja membran reverse osmosis tekanan rendah berdasarkan pada nilai fIuks, permeabilitas, derajat pemekatan, dan nihi rejeksi terhadap sukrosa. TekaTlan optimum membran ultrafiltrasi dan nanofiltrasi bertunrt-tunrt adalah 5 dan 7 bar dengan nilai fluks masing-masing 43.5- 78.81/m2.jam clan 29.2- 50.4I/m2.jam . BerWkan nik fluks dan karakteristik hasil pemurnian, maka rnembran yang tepat bagi proses pemurnian adalah membran ultrafiltrasi. Pengamatan kine j a membran pa& proses pemekatan menggunakan membran reverse osmosis menrmjukkan bahwa konsentrasi umpan yang sernakin tinggi mengakiiatkan penurunan nilai fluks di menitmenit awd semakin tajam, semakin cepat tacapainya nilai fluks konstan, dan semakin meningkatkan tingkat rejeksi mernbran terhadap bahan terlarut. Nilai fluks meningkat dengan meningkatnya tekanan, &an tetapi pa& tekanan tertentu (* bar), tekamn tidak berpengaruh lagi terhahp peningkatan nilai fluks. Membran reverse osmosis bertekanan rendah tip 4820 ULP marnpu memekad;an lamtan mw sugar sampai dengan brks 25.15% d e n p briks awal hasil pemurnian 13.33%. Tekanan operasi yang digunakan adalah 10.6 bar. Larutan raw sugar hasil pemekatan rnenggunakan membran reverse osmosis pada konsentrasi briks 25.15% mempunyai mutu kadar guIa reduksi 3.71%- kadar HK 95.47, dm warna 2 1.85 IU.
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Judul: Distribution and Diversity of Ectoparasite Mites on Geckos in Indonesia
Abstrak: Data on the diversity and dispersal of parasitic mites on house geckos in Indonesia are very scarce. In this work, the distribution and diversity of mites living on three species of house geckos, namely Cosymbotus platyurus, Hemidactylus frenatus, and H. garnotii collected throughout Indonesia, has been elaborated. Geckos and mites were captured and immediately preserved in 70% ethanol. Whole mount of the mites was prepared by clearing in lactophenol followed by mounting on polyvinyl lactophenol solutions. The SEM preparation was conducted to examine the detail morphological characters of the mites. The results showed that among 448 individuals of geckos, 221 geckos were infected by Geckobia mites. Prevalences of C. platyurus, H. frenatus, and H. garnotii infested by mites were 14.8%, 50.69%, and 79.6%, respectively. Three different spesies of Geckobia (G1, G2, and G3) could be differentiated; and based on similarities of their morphological characters to ones described in published literatures, Geckobia G2 is Geckobia glebosum and Geckobia G3 is Geckobia bataviensis while G1 could not be identified to the species level. The highest mean intensity of Geckobia G1 infestation was found on H. garnotii (I=7.0), G. glebosum infestation on H. frenatus (I=3.5), and G. bataviensis infestation on H. garnotii (I=11.8). In general, C. platyurus was infested by the least number of mites. Geckobia G1 were found living on the skin folds on the claws, G. glebosum were found mainly on the body and thigh, and G. bataviensis were found on almost all parts of the host’s body. Geckobia mites are distributed randomly throughout Indonesian Archipelago, following the pattern of distribution of their hosts. So it is concluded that Geckobia G1, G. glebosum, and G. bataviensis are sympatric.
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