Judul: Modification of cassava waste pulp to hydrophilic products by oxidation-grafting
Abstrak: Cassava waste pulp (CWP) from tapioca industrial byproducts present in large numbers. Native starch in CWP has the high potential to raw material, but it possess some undesirable properties limiting its use in industrial applications. These limitations make the research on native starch increased through modification by physically, chemically or enzymatically and resulting in products with a higher added value. The purpose of this study to obtain optimum oxidation conditions of oxidized cassava waste pulp (OCWP) through determining the factors that significantly affect the oxidation process and synthesize hydrogel base OCWP with a character of saline-tolerant. The hydrogels from this study is expected to be a superabsorbent and into the future promising product for agriculture and personal care industries. Potential factors that must be considered in the oxidation process of CWP are temperature, pH, oxidation time, the amount of oxidant and catalyst. The experimental results of the response surface methodology showed the factors that have an important influence on the optimum conditions of oxidation are 78.335 °C temperature, 4.301 ml catalyst and oxidation time of 83.613 minutes. The OCWP was used as the main framework of grafting. Oxidation of CWP produce carbonyl (C=O) and carboxyl (-COO) group which will make it more hydrophilic. Furthermore, the OCWP grafting with acrylic acid (AA) and acrylamide (AM) monomer was optimized for the production of hydrogels. The characterization of oxidation product and hydrogels through the analysis of the IR spectrum and SEM photos. The state of absorbing water (swelling) is the primary parameter of a hydrogel as a candidate of absorbent material. The average of water absorption the OCWP hydrogels is two times higher than the CWP hydrogels. However, both of hydrogel types which are synthesized to be a superabsorbent because it can absorb water up to more than 100 times the dry weight. The Hydrogel swelling capacity in salt solution is significantly reduced compared to swelling in distilled water. However, the effect of NaCl concentration on water absorption capacity for the OCWP-AA and CWP-AM hydrogel has been constantly respectively above of 0.173 M and 0.296 M compared with CWP-AA hydrogel absorption was continuously decreased above of 0.34 M NaCl concentrations. The absorption average difference in the NaCl solution showed the OCWP-AA and OCWP-AM hydrogel has swelling respectively 26 and 12.5 times greater than the CWP-AA hydrogel. Thus, the hydrogel of CWP after oxidation tolerant of saline solution compared with the hydrogel of CWP before oxidation.
Keyword: cassava waste pulp, grafting, hydrogels, oxidation, saline-tolerant

Judul: Sintesis Superabsorben melalui Kopolimerisasi Pencangkokan Asam Akrilat pada Onggok Dialdehida
Abstrak: Cassava waste pulp (onggok) is a residual pulp obtained from starch industry. The purpose of this study is to modify the pulp through oxidation with NaIO4 followed by grafting and crosslinking copolymerization to obtain superabsorbent polymer (SAP). The carbonyl content measurement was utilized to determine the optimum condition for oxidation. Oxidation with 0.05 M NaIO4 for 1 hour and subsequent acetone washing solution gave the best result. Grafting and crosslinking of acrylic acid on the pulp backbone were performed with N,N’- methylene-bis-acrylamide as crosslinker and ammonium peroxidisulfate as the initiator. The synthesis was carried out at 70–75 ºC for 3 hours, then the water absorptive capacity of the copolymer products were determined. Water absorptive capacity of SAP was 893.22 g/g in 24 hours. The maximum absorptive capacity of SAP in solutions with pH ranging from 2 to 11 was 915.26 g/g at pH 9, whereas the maximum absorptive capacity in salt solutions were obtained at 0.01 M NaCl, namely 137.42 g/g.
Keyword: absorptive capacity, acrylic acid, cassava, oxidation, superabsorbent

Judul: Karakteristik Suara Song Burung Kenari (Serinus canaria) Postur Besar dan Kecil.
Abstrak: Burung kenari (Serinus canaria) memiliki nyanyian yang sangat bervariasi dengan durasi yang panjang dan merupakan tipe burung bernyanyi open learners. Penelitian ini bertujuan menganalisis karakteristik suara song burung kenari (Serinus canaria). Penelitian dilakukan pada bulan April sampai Juni 2017 di Bogor, Jawa Barat. Perekaman suara song terhadap 12 ekor burung kenari jantan dilakukan dengan menggunakan mikrofon Sennheiser ME66 dan alat perekam Sony PCM-D50. Burung kenari yang digunakan merupakan burung yang pernah mengikuti kontes burung kicau dan memiliki predikat juara kontes burung. Amplitudo, durasi suara, frekuensi, dan volume suara burung dianalisis dengan menggunakan software Raven Pro 1.4. Data tersebut selanjutnya dianalisis deskriptif. Hasil analisis suara menunjukkan bahwa burung kenari memiliki banyak syllable, suara song rapat dan tidak terputus-putus, tempo yang cepat, dan adanya pengulangan suku kata pada setiap suara song. Burung kenari postur kecil memiliki rataan durasi lebih panjang dibandingkan dengan kenari postur besar, tetapi burung kenari besar memiliki rataan max amplitudo, average power, max power, min amplitudo, peak amplitudo, dan peak frekuensi.
Keyword: karakteristik suara (song), kenari, syllable