Judul: Model Simulasi Perawatan Mesin dan Fasilitas Industri
Abstrak: Perawatan mesin merupakan kegiatan memelihara fasilitas atau peralatan pabrik, mengadakan perbaikan, penyesuaian atau pergantian yang diperlukan supaya terdapat keadaan operasi yang memuaskan. Permasalahan utama perawatan mesin yaitu biaya perawatan yang tinggi . Oleh karena itu perlu dilakukan efisiensi pada bagian perawatan mesin melalui penggunaan mesin yang ekonomis dan efisiensi terhadap antrian perbaikan mesin di bengkel. Dalam ha1 ini teknik yang digunakan adalah teknik analitis melalui metode simulasi. Simulasi kejadian pada antrian di bengkel dengan tingkat waktu antar kedatangan kerusakan rata - rata 39.58 jam per kerusakan, waktu perbaikan per kerusakan listrik rata - rata .- 67.35 jam dengan keragaman 15.88 jam, waktu perbaikan per kerusakan mekanik r a t a - r a t a 41.19 jam dengan keragaman 30.88 jam, dan kemungkinan t e r j a d i kerusakan l i s t r i k 0.30 s e r t a kemungkinan t e r j a d i kerusakan mekanik 0.70, diperoleh h a s i l bahwa r a t a - r a t a lama mesin berada d i bengkel l i s t r i k 71.06 jam dan di bengkel mekanik 46.58 jam, waktu tunggu r a t a - r a t a mesin untuk d i p e r b a i k i 5 jam dan panjang a n t r i a n d i bengkel l i s t r i k 0.03 dan dibengkel mekanik 0.10.
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Judul: Implementation of smith and dekker’s model on rotary kiln machine (Case Study: PT Semen Indonesia (Persero) Tbk)
Abstrak: PT Semen Indonesia (Persero) Tbk merupakan perusahaan yang bergerak di bidang industri manufaktur yang memproduksi semen. Salah satu mesin yang sangat penting dalam menentukan kualitas produksi semen yaitu mesin rotary kiln. Mesin rotary kiln adalah salah satu mesin dalam unit pembakaran yang berfungsi menghasilkan terak yang merupakan bahan dasar semen. Kerusakan yang muncul pada mesin ini dapat menimbulkan gangguan terhadap proses produksi dan akan menghambat kelangsungan produksi mesin yang lain. Model Smith dan Dekker menggabungkan model ketersediaan dan model perawatan preventif dengan memperhatikan uptime dan downtime dari sistem. Model ini disebut sebagai model 1 out of n system, yaitu sebuah model yang terdiri atas satu mesin yang beroperasi dan didukung oleh (n-1) buah mesin cadangan. Model 1 out of n system juga dapat diterapkan pada komponen-komponen yang dapat diganti. Dengan mengetahui perkiraan uptime dan downtime sistem, dapat diperoleh perkiraan yang baik untuk rata-rata biaya perawatan dalam jangka waktu panjang. Berdasarkan analisis perhitungan uptime, downtime, dan biaya serta peluang sukses mesin dengan pertimbangan ketersediaan jumlah komponen mesin cadangan, diperoleh waktu penggantian yang optimal untuk defuser, kiln drive, cooler, dan alarm yaitu 74.66 jam. Selain itu, banyaknya komponen mesin cadangan yang optimal untuk defuser, kiln drive, cooler, dan alarm sebesar 4 unit., PT Semen Indonesia (Persero) Tbk is a company which engages in infrastructure that produces cement. One of machines that is so important to determine the quality of cement production is rotary kiln machine. Rotary kiln machine is one of machines in the combustion unit which produces slag that is used in the main substance of cement. The damage of this machine can disrupt the production process and stop the activities of other machines. Model by Smith and Dekker combines machines availability and preventive maintenance models by considering the expected uptime and downtime of the system. This model is called as 1 out of n system model, which has one operating machine and supported byy (n-1) units of the reserve machines. A1 out of n system is also applicable to replaceable components. By knowing approximation of the expected uptime and downtime of the system, a good approximation for the long term average maintenance costs can be obtained. Based on the calculation analysis of the uptime, downtime, and cost with the chances of a successful machine with consider the number of the reserve machine components, the optimal replacement times of defuser, kiln drive, cooler, and alarm are 74.66 hours. Moreover, the optimal number of the reserve machine components of defuser, kiln drive, cooler, and alarm are 4 units.
Keyword: biaya perawatan, model 1 out of  n system, rotary kiln, waktu penggantian

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