Judul: Pengaruh Konsentrasi Urea Terhadap Karakteristik Hidrogel Asam Akrilat-Akrilamida Berbasis Karagenan.
Abstrak: Dalam rangka meningkatkan efisiensi pemupukan, telah dilakukan sintesis hidrogel dengan metode ikat silang kimia dan variasi konsentrasi pupuk urea 0, 5, dan 10 %. Bahan dasar yang digunakan adalah asam akrilat, akrilamida, dan karagenan. Pengujian yang dilakukan meliputi uji sewlling, fraksi gel, kinetika swelling, uji mekanik, pemuatan dan pelepasan pupuk. Hasil penelitian menunjukkan hidrogel paling optimum untuk media pelepasan pupuk adalah hidrogel dengan konsentrasi urea 5 %, pada konsentrasi tersebut hidrogel mencapai swelling paling tinggi yaitu sebesar 26168,5 %, sifat mekanik juga paling kuat pada konsentrasi 5 % dimana nilai hardness sebesar 1,36 N. Selain itu, pelepasan pupuk urea pada konsentrasi 5% juga lebih lambat dibandingkan 10%, Pelepasan pupuk pada hidrogel dengan konsentrasi urea 5 % berkisar antara 16 % sampai 18 % selama 4 hari pengukuran, akan tetapi kedua perlakuan konsentrasi 5 % dan 10 % memiliki kecenderungan pelepasan yang sama, dimana pelepasan cenderung cepat pada 5 jam pertama dan mulai stabil pada pengukuran 24 jam. Oleh karena itu, berdasarkan beberapa respon pengujian dapat disimpulkan bahwa perlakuan konsentrasi urea 5 % lebih optimal untuk hidrogel sebagai media pelepasan pupuk terkendali., In order to increase fertilization efficiency, hidrogel synthesis has been carried out by chemical crosslinking method and variations in urea fertilizer concentrations of 0, 5, and 10%. The basic ingredients used are acrylic acid, acrylamide, and carrageenan. Tests carried out include sewlling tests, gel fractions, swelling kinetics, mechanical tests, fertilizer loading and release. The results showed that the most optimal hydrogel for fertilizer release media was a hydrogel with a urea concentration of 5%, at that concentration the hydrogel reached the highest swelling of 26168.5%, mechanical properties were also the strongest at a concentration of 5% where the hardness value was 1.36 N. In addition, the release of urea fertilizer at a concentration of 5% was also slower than 10%, the release of fertilizer on hidrogel with a urea concentration of 5% ranged from 16% to 18% for 4 The day of measurement, however, both 5% and 10% concentration treatments have the same tendency to release, where release tends to be rapid in the first 5 hours and stabilizes at 24 hours. Therefore, based on several test responses, it can be concluded that a urea concentration treatment of 5% is more optimal for hydrogel as a controlled fertilizer release medium.
Keyword: hidrogel, karagenan, pupuk urea, carrageenan, chemical, hydrogel, urea fertilizer

Judul: Sintesis Hidrogel Berbasis Karagenan pada Aplikasi Pemupukan: Variasi Konsentrasi Metilenbisakrilamida.
Abstrak: Hidrogel adalah jaringan polimer tiga dimensi pada polimer hidrofilik dengan ikatan silang yang mempunyai kemampuan menyerap air. Karagenan sebagai polimer alami dipilih karena dapat berikatan dengan asam akrilat dan membentuk gel yang baik dan elastis. Hidrogel disintesis menggunakan larutan karagenan dengan asam akrilat dan diikat silang menggunakan MBA dengan variasi konsentrasi sebesar 0,5 dan 1%. Pengujian hidrogel menganalisis nilai swelling, fraksi gel, kelengketan, kekerasan, pemuatan dan pelepasan pupuk. Kekuatan hidrogel dipengaruhi oleh MBA, perlakuan MBA 1% tanpa termuat urea menjadi perlakuan terbaik dalam penelitian ini karena memiliki nilai kekerasan yang tidak terlalu tinggi dan nilai fraksi gel yang tinggi. Dari hasil yang didapat, hidrogel berbasis karagenan belum mampu diaplikasikan sebagai pupuk lepas lambat karena tingkat pelepasan mencapai 21% pada satu jam pertama pengukuran. Memiliki nilai swelling yang tidak rendah dengan kemampuan pemuatan pupuk cukup tinggi dan signifikan dalam menahan pelepasan pupuk menjadi parameter yang penting dalam hidrogel., Hydrogels are three-dimensional polymer networks on hydrophilic polymers with cross-links that have the ability to absorb water. Carrageenan as a natural polymer was chosen because it can bind with acrylic acid and form a good and elastic gel. Hydrogels were synthesized using a solution of carrageenan with acrylic acid and crosslinked using MBA with varying concentrations of 0.5 and 1%. Hydrogel testing analyzed the value of swelling, gel fraction, stickiness, hardness, loading and releasing of fertilizers. Fertilizer loading was carried out using a urea solution of 0 and 5% concentration. Hydrogel strength was affected by MBA, 1% MBA treatment without urea loading was the best treatment in this study because it had a hardness value that was not too high and a high gel fraction value. From the results obtained, carrageenan-based hydrogel could not be applied as a slow release fertilizer because the release rate reached 21% in the first hour of measurement. Having a swelling value that is not low with sufficiently high and significant fertilizer loading ability to restrain fertilizer release is an important parameter in hydrogels.
Keyword: Crosslinking agent, hydrogel, carrageenan, urea release

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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