Judul: Penentuan Rute dan Jenis Kendaraan yang Optimal pada Distribusi Barang Menggunakan Integer Linear Programming
Abstrak: Salah satu masalah yang dihadapi suatu perusahaan adalah menentukan rute kendaraan untuk distribusi produk. Rute distribusi ini mencakup jalur perjalanan kendaraan untuk mengantar produk dari asal ke tujuan. Permasalahan penentuan rute distribusi dapat dimodelkan sebagai multi-depot vehicle routing problem (MDVRP). Model MDVRP diformulasikan menggunakan integer linear programming (ILP) dan didapatkan dengan menggunakan perangkat lunak LINGO. Dalam penelitian ini dibahas model rute untuk distribusi barang dengan lebih dari satu depot dan jenis kendaraan lebih dari satu. Model ini diimplementasikan pada kasus distribusi alat kesehatan. Pada kasus ini terdapat dua pusat distribusi dan tiga belas cabang. Setiap pusat distribusi memiliki dua kendaraan dengan jenis yang berbeda. Hasil yang didapatkan dari model menunjukkan biaya minimal sebesar empat belas juta enam puluh ribu seratus rupiah. Solusi model memberikan tipe kendaraan yang digunakan dari setiap pusat distribusi, serta rute setiap kendaraan dalam melayani cabang, dan solusi ini memberikan biaya yang minimum.
Keyword: distribution route problem, MDVRP, multi-depot vehicle routing  problem

Judul: Penentuan Lokasi Gudang dan Rute Pendistribusian Menggunakan Integer Programming
Abstrak: Distributing is one of important activities in a company. The efficiency of distribution costs can increase company profits. In this context the problems faced by the company are to reduce distribution costs including the determination of the warehouse location and the distribution route. In this paper, two mathematical models are studied. Those are the model for determining the warehouse location and the distribution route. Models are formulated in term of integer programming. In implementation, we consider a logistic company which has 1 distribution center, 2 warehouses, 3 suppliers, 40 customers, and 24 trucks with different capacities. The company plans to establish at most 3 new warehouses. It is demonstrated that, by using the models, two new locations of warehouse are recommended and an optimal distribution route is provided.
Keyword: warehouse location, distribution routing, distribution

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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