Judul: Masalah Penentuan Koridor Bus dalam Meminimumkan Biaya Operasional
Abstrak: Population’s mobility in Jakarta is extremely high. This would require adequate public transportation facilities. One of the mass public transportation systems developed in Jakarta is bus rapid transit system, which is better known as busway. Busway is expected to be a public transport that would be able to serve the population’s mobility. Currently, the busway is still subsidized by the government, because the fare is set relatively low (in order to attract people using the busway). Nevertheless, the operational cost is relatively high. This paper presents an optimization model to determine the corridors of the busway to be operated as well as the frequency of the buses at each corridor. This optimization is formulated in order to fulfill the demand of transportation for each pair of origin-destination and, at the same time, to minimize the total operational cost. This problem is formulated as a integer nonlinear programming and solved using Lingo software 11.0.
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Judul: Penentuan Frekuensi Bus Rapid Transityang Diaplikasikan pada Bus Trans Mataram Metro dalam Meminimumkan Biaya Operasional
Abstrak: Pelayanan angkutan umum di Kota Mataram saat ini berada dalam kondisi yang cukup memprihatinkan. Masyarakat lebih memilih menggunakan kendaraan pribadi baik sepeda motor maupun mobil pribadi. Untuk mengatasi hal tersebut permerintah menyediakan angkutan umum yang lebih efisien, aman, nyaman dan terjangkau oleh daya beli masyarakat yaitu Bus Rapid Transit (BRT). Pengoperasian BRT yang baik dapat memberikan tingkat mobilitas yang tinggi dengan biaya operasional yang minimum. Salah satu caradalam meminimumkan biaya operasional yaitu dengan mengoptimalkan frekuensi bus yang beroperasi. Frekuensi bus yang optimal dicapai jika semua demandpenumpang terpenuhi. Oleh karena itu, penelitian ini bertujuan untuk membuat model matematika penentuan frekuensi BRT dan mengaplikasikan model tersebut pada sistem layanan bus Trans Mataram Metro. Model matematika penentuan frekuensi bus dibentuk ke dalam integer linear programming (ILP). Variabel keputusan yang ditentukan yaitu frekuensi bus yang bergerak dari terminal i ke terminal j untuk koridor k dan jumlah penumpang yang terangkut pada setiap ruas jalan dengan fungsi tujuan meminimumkan total biaya operasional kendaraan. Beberapa skenario pengujian model digunakan untuk melihat kesesuaian hasil dari model. Pada penelitian ini digunakan lima contoh kasus yang solusinya telah diketahui dengan memberikan demanddan biaya operasional koridor di ruas jalan yang berbeda-beda. Berdasarkan aplikasi model pada sistem layanan bus Trans Mataram Metro diperoleh bahwa pergerakan bus dapat memenuhi semua demanddi setiap ruas jalan. Kesembilan koridor yang dilayanani oleh bus Trans Mataram Metro menghasilkan total biaya operasional kendaraan paling minimum senilai Rp5 208 880 772 dengan frekuensi bus terendah melalui koridor 1 yaitu sebanyak 36 kali, sedangkan frekuensi bus tertinggi melewati koridor 5 sebanyak 7492 kali.
Keyword: frekuensi bus, Bus Rapid Transit, minimum biaya operasional, integer linear programming

Judul: Synthesis of Apatite - Chitosan Composite Using Duck Eggshell and Chitosan with Temperature and pH Control
Abstrak: Composite of apatite-chitosan was prepared by using chitosan as polymer matrix. Calcium phosphate was prepared from CaO and (NH4)2HPO4, which the ratio Ca : P had to be 1.67. Chitosan is produced by deacetilase from biopolymer chitin. Duck eggshell (95% CaCO3) as starting material was converted to be calcium oxide (CaO) through calcinations with temperature 1000oC for 5 hours. In-situ and ex-situ methods were prepared from apatite and chitosan (dissolved with acetate acid 2%). Calcium phosphate prepared for bone implantation, but it is too fragile and brittle to be implant into the body. So addition of chitosan can decrease crystalinity and increase mechanic characteristic (tougher). Composite apatite-chitosan was resulted by fast precipitation. Fast precipitation was held in a breaker glass with nitrogen atmosphere, under controlled temperature at 37oC and pH 7, in order to increase amount of hydroxyapatite. Precipitation with CaO which was dropped by (NH4)2HPO4. Hydroxyapatite and chitosan were appearing at samples with in-situ and ex-situ methods which indicating by peak matching of XRD (closed lattice parameter, crystal size), overlapping at FTIR spectra and supporting by SEM picture (homogenous and agglomerated particle). However, it still needs further research to examine biocompatibility osteoconductive degree of sample by in-vivo and in-vitro test.
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