Judul: Uni kerja dan analisis energi reaktor tipe static mixer untuk produksi biodiesel secara katalik
Abstrak: Kebutuhan energi dunia terus meningkat. Sementara itu ketersediaan sumber energi, berupa energi fosil yang selama ini menyokong kebutuhan tersebut semakin berkurang. Berbagai upaya terus dilakukan untuk mengatasi masalah tersebut. Diantaranya adalah dengan mencari sumber energi baru dan konversi energi dari bahan bakar fosil ke bahan alternatif yang terbarukan. Biodiesel merupakan salah satu bentuk energi alternatif yang saat ini sedang giat dikembangkan.
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Judul: Kajian Daur Ulang Panas Pada Produksi Biodiesel Secara Non-katalitik Berdasarkan Analisis Eksergi
Abstrak: Katalitik dan non-katalitik merupakan dua metode yang digunakan untuk memproduksi biodiesel sampai saat ini. Keduanya memiliki kelebihan dan kekurangan. Metode non-katalitik tidak membutuhkan katalis sehingga alur produksi lebih pendek, lebih ramah lingkungan, lebih sederhana, dan tidak perlu menghilangkan free fatty acid (FFA) dari minyak (Joelianingsih 2008b). Namun, kelemahannya membutuhkan rasio molar antara metanol dan minyak lebih tinggi (24-42) dan suhu yang digunakan untuk mereaksikan pada reaktor sangat tinggi (240-350oC) sehingga energi yang dibutuhkan untuk menaikkan suhu pun tinggi (Saka dan Kusdiana 2001). Menurut Sigalingging (2008) rasio energi yang didapat sebesar 0.84, masih lebih rendah dibandingkan dengan produksi secara katalitik, yaitu sebesar 0.98. Oleh karena itu, perlu dilakukan penyempurnaan guna meningkatkan performansi alat, sehingga rasio energi yang didapat lebih tinggi. Rasio energi dapat ditingkatkan dengan meminimalisasi energi yang tidak termanfaatkan selama proses produksi, salah satunya dengan pemanfaatan (daur ulang) panas dalam sistem dengan merancang alat penukar panas (APP) yang diharapkan mampu memaksimalkan energi yang dapat dimanfaatkan. Tujuan dari penelitian ini adalah 1). Merancang penukar panas yang berfungsi untuk mendaur ulang panas dari reaktor ke evaporator. 2). Menghitung rasio energi produksi biodiesel secara non-katalitik. 3). Melakukan analisis eksergi pada sistem produksi biodiesel non-katalitik.
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Judul: Phylogeography and Species Limits in the Papuan White Snake (Micropechis ikaheka) (Reptilia: Serpentes: Elapidae)
Abstrak: Papua white snake, Micropechis ikaheka, has been distingushed into two subspecies M.i. ikaheka and M.i. fasciatus. However, due to lack of data on their morphology, distribution and ecology, both subspecies often ignored in scintific discussions and refers only byas , Micropechis ikaheka. This study was designed to document the differences between M.i. ikaheka and M.i fasciatus by using scales characteristics and reproductive organ or hemipenes. The study also examine, zoogeography, habitat, diet and cannibalism of both subspecies to better understanding the the ecology of one of the most venomous snakes in the world. This study consists of three topics with method and also different in the size samples, respectively. The first study is the histology and microtopography of the skin were studied using paraffin method and Scanning Electron Microscope (SEM). The second is the hemipenis were examined by following Myers and Cadle (2003), and Zaher and Prudente (2003). The third is the abdominal surgery was carried out to document diet type and the investigate phenomenon of cannibalism in the snake. Specimens for this study came from the collection from Museum Zoologicum Bogoriense (MZB) and Universitas Negeri Papua’s Laboratory (LZU). The research result also indicated that the markers of skin and hemipenis described the same structure and microornamentation in all M. ikaheka groups being compared. Based specimens examined morphological descriptions do not s support the further differentiation in Micropechis. In short, two markers that used in this study could not sufficiently indicate the differences in the level of species and subspecies of M. ikaheka. The study, however, were able to delineate zoogeography and skin color patterns, which fall into four groups: M. i. ikaheka; M. i. fasciatus. M. i. ssp. “intermediate”; and M. i. ssp “black”. This study also revealed that color variations did not overlap in their geographic distribution. It is therefore, it suggested that environmental factors may contribute to the skin color variations. It also assumed that habitat discontinuous and biogeography factors may also cause the loss of the connection between the original populations (vicarians) or follow colonization events (dispersal). The examined of 22 stomach contents of M. ikaheka shows this species is carnivorous, and prey on vertebrates such as amphibians, fish, reptiles, and Mammals. These snakes are opportunistic predators since they prey on all that can be captured, but mainly reptiles (61.5%), followed by mammals and fish (both 15.4%), and amphibians (7.7%). Although categorized as terrestrial animal, the diet study showed that M. ikaheka snakes often go into the water to hunt for fish (the sample from Yapen island), including eel (the sample from Aru island). Based on prey items indentified, there is evidence that M. ikaheka is cannibal. At this time, there still no record on reason for cannibalism, but it is assumed that cannibalism was due to competition between populations and means to control population.
Keyword: geographic variation, white snake, papua