Judul: Sintesis Superabsorben Onggok-Poliakrilat yang Diperkaya dengan Urea
Abstrak: Fertilizer-enriched superabsorbent polymer (SAP) could be used to help water savings, especially in dry areas, and improve the efficiency of fertilizer application compared with conventional method, stocking of fertilizer on the soil surface. In this research, several kinds of SAP were synthesized by grafting copolymerization of 40% neutralized acrylic acid with onggok (solid waste of tapioca factory) by using ammonium persulfate as initiator and by varying the amount of crosslinker N,N'-methylene-bis-acrylamide and urea added. Water absorption capacity of SAP before enrichment was 730.48 g/g with nitrogen content of 4.12%, and decreased after enriched by urea. For 0.025, 0.050, and 0.100 g of crosslinker, water absorption capacities were 293.38, 227.34, and 209.20 g/g and nitrogen contents were 17.99, 16.49, and 16.83%, respectively. Nitrogen release study of enriched SAP with 0.025 and 0.050 g of crosslinker showed nitrogen release of 6.29 and 7.35%, respectively while SAP with 0.100 g of crosslinker at the same time only released 23.92% of nitrogen. These results indicated that the amount of crosslinker greatly influenced the pattern of release of urea.
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Judul: Pengayaan Superabsorben Onggok-Poliakrilamida dengan Urea Melalui Metode Perendaman.
Abstrak: Superabsorbent can be synthesized from onggok and polyacrylamide using ammonium persulfate and N,N'-methylene bis-acrylamide through grafting-crosslinking methods. Superabsorbent can be enriched with urea fertilizer with slow nutrient-release properties. This superabsorbent enrichment can overcome the losses caused by conventional urea use because urea contains nitrogen nutrient which utilization efficiency is difficult to be increased. Enrichment of superabsorbent with urea was carried out by soaking superabsorbent in urea solution. Maximum enrichment was obtained in superabsorbent soaked in 1000 ppm urea solution for 17 and 24 hours with loading percentage of 36.72 and 32.48%. The release of nitrogen was tested in static aqueous media. Superabsorbent immersed in 1000 ppm urea solution for 17 hours released nitrogen most slowly, in 5 days. Release rate of nitrogen was 0.0370 ppm/min, and the nitrogen release pattern was in accordance with the pattern of plant nutrient uptake.
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Judul: Beberapa aspek anatomi alat sirkulasi ruang dada kancil
Abstrak: Telah dilakukan penelitian dengan menggunakan 10 ekor kancil dewasa jantan dan betina dengan tujuan untuk menge- tahui beberapa aspek anatomi alat sirkulasi di dalam ruang dada, meliputi jantung, pembuluh darah yang keluar dan ma- suk jantung serta ukuran-ukuran jantung. Kancil merupakan ruminansia terkecil di dunia, hidup di daerah tropika India, Thailand, Malaysia dan Indonesia bagian barat. Hewan ini dilindungi dan mempunyai prospek yang baik untuk hewan penelitian maupun dibudidayakan. Hasil penelitian menunjukkan bahwa berat jantung rаta-rata adalah 0.69% dari berat rata-rata kancil. Dan ini mirip pada jantung kuda dan anjing. Bentuk jantung lonjong seperti halnya ruminansia. Demikian pula letaknya di dalam ruang dada seperti pada ruminansia dengan adanya Ligamentum sternopericardiacum. Di dalam ventrikel kanan membersit sebuah Musculus (M.) papillaris dari dindingnya dan tiga sampai empat Musculi (Mm.) papillares dari Septum interventriculare. Hanya dua buah Mm. papillares yang berukuran besar dibersitkan dari dinding ventrikel kiri. Percabangan Arteri (A.) coronaria sinistra lebih dominan dari pada A. coronaria dextra. Sedangkan A. sub clavia sinistra dicabangkan langsung dari aorta di dorso- caudal pembersitan Truncus (Tr.) brachiocephalicus…
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