Judul: Pemanfaatan Lateks Karet Alam Sebagai Bahan Pemodifikasi Aspal Untuk Meningkatkan Mutu Perkerasan Jalan Aspal.
Abstrak: Indonesia is the second largest producer of natural rubber in the world after Thailand. Indonesia's natural rubber production in 2007 reached 2.55 million tons per year. However, Indonesia's natural rubber production has decreased due to the global crisis that occurred in 2008. One of the sectors directly affected by the crisis is the automotive industry which is the largest consumer of natural rubber in the world. On the other hand, economic growth will increase the traffic load in terms of quantity, weight and speed. The burden of heavy traffic, road surface temperature reaches 70oC, high rainfall and the poor drainage, causing the road can be easily damaged. Therefore, paving way’s modification is required to fulfill those needs, one with the latex modified asphalt. The purposes of this study were to determine the effect of types and additional doses of latex in the asphalt toward penetration value and softening point which affecting the quality of asphalt pavement and to get the best mixture of asphalt to improve the quality of asphalt road pavement. This research methodology consiststed of two stages, namely preparation of raw materials (determination of the nature and characteristics of latex and latex depolymerization process) and the main research (the mixing process of latex into the asphalt and testing). Experimental design used in this study was Complete Random Factorial design with two replications for each treatment. Factors that influence were types and additional doses of latex rubber in the asphalt with each level of 8 and 3. There were two types of latex used in this study, namely concentrated latex which have dry rubber content (DRC) and depolimerization latex (latex which has decreased due to the molecular weight of polymer bonds break). Depolimerization latex in this study employed chemical methods with reduction-oxidation reaction (redox) with hydrogen peroxide (H2O2) as an oxidant and sodium hypochlorite (NaClO) as a reductant. In general, asphalt modification which has produced fulfill the quality requirements or quality standards for asphalt polymer at the value of penetration and softening point. Quality standard of penetration value is 50-75 dmm, whereas minimum value for softening point is 54oC. Modification of asphalt penetration values ranged from 49.33 to 61.25 dmm. There are two types of asphalt modifications outside the standard value, namely the modification of asphalt with a penetration of 49.52 and 49.33. Softening point value of asphalt modification ranged from 56.11oC to 65.27oC. The best asphalt modification was L5K5 sample (depolimerization latex with 5% additional doses of rubber in asphalt). Selection of the best asphalt modification was not only determined by the suitability of the penetration value and softening point with quality standard, but also was determined by homogenity between the asphalt dan rubber.
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Judul: Pengembangan proses degradasi karet alam menggunakan lindi hitam sebagai bahan tambahan aspal termodifikasi
Abstrak: One way to improve the usability of natural rubber is by modifying natural rubber, for example by giving a chemical degradation treatment. Degradation of chemical compounds taken with the aid of a polymer chain breakers, in this study used black liquor. Degradation of natural rubber aims to adjust the physical properties of natural rubber in the mechanism of mixing with asphalt to produce a modified asphalt that is expected to improve and enhance the properties of asphalt in its application in road pavement. Chemical degradation pursued through three stages. The first stage is the formation process of latex into solid rubber in the form of crepes. The second stage is the process of rubber degradation using black leachate by using two variations of the treatment, immersion time of rubber in black leachate and drying time. While the third stage is mixing of degraded rubber with asphalt. The variation of immersion time and drying time significantly affected the amount of black liquor absorbed by the rubber, plasticity (Po), and softening point of modified asphalt. The best treatment in this study were treated R7K2 (rubber immersed for 7 hours and dried in the normal time plus 2 hours).
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Judul: Karakteristik Anatomi Skelet Kepala Buaya senyulong (Tomistoma schlegelii).
Abstrak: Buaya sepit atau senyulong (Tomistoma schlegelii) merupakan jenis buaya asli Indonesia yang berhabitat di sungai-sungai Sumatera, Kalimantan, dan juga pedalaman Sulawesi. Salah satu ciri khas buaya senyulong adalah bentuk moncong yang runcing dan sempit, namun hingga saat ini informasi mengenai struktur skelet kepala buaya senyulong sangat terbatas. Penelitian ini bertujuan untuk mempelajari karakteristik anatomi skelet kepala buaya senyulong yang dikatikan dengan fungsi dan perilakunya. Penelitian dilakukan secara eksploratif dengan melakukan pengamatan, pencatatan, dan pengambilan gambar dari skelet kepala buaya senyulong. Skelet kepala berukuran panjang 70 cm, lebar 29 cm, dan tingggi 17 cm dengan permukaan kasar pada os nasale, os frontale, os maxilla, os mandibula, os lacrimale, os jugale. Jumlah gigi pada buaya ini sebanyak 78 buah, terdiri dari 4 buah gigi premaxila, 16 buah gigi maxila, dan 19 buah gigi mandibula. Pada regio orbitalis ditemukan dua pasang fenestrae temporales yang berkembang baik. Fenestra supratemporale merupakan lubang oval yang membentang di sepanjang os parietale. Fenestra infratemporale berbentuk segitiga dan dibatasi oleh os squamosum, os postorbitale, os jugulare, dan os quadratum. Os mandibula hewan ini mempunyai symphysis mandibularis yang panjang yaitu garis yang melintang di corpus mandibulae. Secara fungsional ukuran symphysis mandibularis berkaitan dengan adaptasi hewan terhadap diet makan.
Keyword: kepala, moncong, Tomistoma schlegelii