Judul: Release Pattern of Urea from Onggok-Polyacrylamide Copolymer Superabsorbent at Various Level of Crosslinking.
Abstrak: Rendahnya efisiensi penyerapan urea oleh tanaman akan menimbulkan kerusakan pada tanaman itu sendiri dan mencemari lingkungan. Polimer superabsorben (SAP) yang diperkaya urea digunakan dalam upaya peningkatan efisiensi penyerapan urea oleh tanaman. SAP disintesis dengan kopolimerisasi pencangkokan-penautan-silang akrilamida pada onggok (limbah padat singkong) dengan jumlah penaut-silang beragam (50, 75, dan 100 mg). Proses saponifikasi dilakukan untuk meningkatkan daya serap air SAP. Keberhasilan proses pencangkokan-penautan-silang ditunjukkan oleh spektrum inframerah transformasi Fourier. Pengayaan SAP yang diperoleh dengan urea dilakukan dengan cara merendamnya dalam larutan urea 1000 ppm dan diteliti laju pelepasan dalam air secara statis. Model matematika laju pelepasan urea, yang didasarkan pada model pertumbuhan logistik jenis hubungan eksponensial 2, dikembangkan untuk menggambarkan perubahan konsentrasi urea terhadap waktu. Laju pelepasan yang paling rendah sebesar 0.81 ppm/menit ditunjukkan oleh SAP dengan penaut-silang 100 mg. Pola laju pelepasan urea pada SAP yang semakin rendah mengindikasikan penyerapan urea oleh tanaman lebih efisien dibandingkan pemberian urea secara konvensional.
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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: Etno-ornitologi Burung Kancilan Flores (Pachycephala nudigula nudigula Hartert 1897) pada Masyarakat Lio di Taman Nasional Kelimutu
Abstrak: Bare-throathed whistler is one of several wild birds in Kelimutu National Park (TNKL) that is believed to have correlation with Lio Community‟s belief. The estimation of Bare-throated whistler‟s population in Kelimutu National Park was about 186.41-1668.07 individual by the density about 0.0389-0.3481 ind/ha with the sex ratio 6.2:1 that spreaded on area with height of 1100 – 1600 masl. The characteristic of Bare-throated whistler‟s habitat is a natural forest with various canopy level, high plant species diversity and high density. The habitat characteristics related to the availability of food in the form of insects, cover, safety and a nesting site. Generally the most of Lio community knew the existence of Bare-throated whistler directly or from their parents‟ stories. The perceptions of Lio Community to the Bare-throated whistler‟s existence is generally support the conservation efforts. The perceptions construct the Lio Community‟s atitude that tend to be conservative to the existence of Bare-throated whistler. The attitude shown by their behavior that not cathing the Bare-throated whistler from the TNKL‟s area or the outside. The attitude have an important role to the existence of Bare-throated whistler in Kelimutu National Park‟s area.
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