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 filtrasi sari buah nanas dengan menggunakan membran selulosa asetat
Abstrak: Membran merupakan lapisan tipis semipermeabel diantara dua fasa yang berbeda karakter, fasa pertama adalah feed atau larutan pengumpan dan fasa kedua adalah permeat atau hasil pemisahan. Salah satu fungsi membran adalah memisahkan materi berdasarkan sifat fisiknya (Hartomo, 1994). Teknologi membran telah banyak dimanfaatkan dalam berbagai bidang aplikasi, sep erti pada teknologi industri pangan, biologi, kimia dan kesehatan. Teknologi ini merupakan pilihan yang tepat untuk keperluan penyaringan, pemisahan dan pemurnian.Pada penelitian ini digunakan membran selulosa asetat untuk memfilter sari buah nanas hingga dapat dihasilkan sari buah nanas murni. Selain itu penelitian ini juga bertujuan untuk mengetahui perubahan nilai fluks membran dan nilai konduktansi membran akibat fouling pada pori-pori membran setelah proses filtrasi serta sifat fisik dan pH sari buah nanas sebelum, setelah dan sisa proses filtrasi. Pada proses filtrasi dengan pengadukan 22 cm/s dan tekanan sebesar 1,021 x 105 Pascal efisiensi membran tinggi, hal tersebut dapat terlihat dari jumlah fluks yang dihasilkan selama proses filtrasi yang cukup tinggi. Akan tetapi berdasarkan hasil dari pengukuran sifat fisik dan pH sari buah nanas yang telah difilter dan sisa filtrasi serta persentase perubahannya terhadap sari buah nanas yang belum diflter, proses filtrasi sari buah nanas tanpa perlakuan apapun memberikan nilai kerja membran yang baik. Penurunan nilai fluks membran dengan bertambahnya waktu filtrasi dan semakin kecilnya jari-jari pori membran menunjukkan telah terjadi peristiwa fouling pada proses filtrasi
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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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