Judul: Masalah Penentuan Rute Kendaraan Antarjemput Roti
Abstrak: Product distribution is one of important activitis for a company. In this paper we discussed a pickup and delivery problem in a company. The objective is to find an optimal route in the framework of vehicle routing problem with pickup and delivery with time windows (VRPPDTW). We provided an illustrative example which describes a pickup and delivery process in a bread company with 1 depot, 10 customers, and 7 units of vehicles. In the first stage we decided the minimum number of vehicles required. Then, in the second stage, we determined the route with minimum cost. LINGO 11.0 is utilized in solving the problem.
Keyword: vehicle routing problem, time windows, pickup and delivery product, optimum

Judul: Vehicle Routing Problem pada Distribusi Sayuran Organik
Abstrak: Pengendalian permasalahan yang terjadi pada distribusi sayuran organik dapat diselesaikan dengan Multiple Trip Vehicle Routing Problem for Multiple Product and Compartments with Time Windows (MTVRPMPCTW) dan diselesaikan dengan salah satu metode eksak, yaitu Integer Linear Programming. Aplikasi model dilakukan terhadap tiga kasus berbeda, pelayanan 5 lokasi dengan rute tunggal, pelayanan 10 lokasi dengan rute majemuk, dan pelayanan 15 lokasi dengan rute majemuk serta adanya time windows yang harus terpenuhi. Pada kasus 10 lokasi dan 15 lokasi, kendaraan yang telah selesai mengantarkan sayuran organik harus kembali ke depot dan dapat melakukan lebih dari satu kali proses distribusi apabila masih terdapat lokasi yang belum dilayani. Setiap lokasi pada seluruh kasus dapat memesan lebih dari satu jenis sayuran organik. Produk yang dikirim akan ditempatkan di kompartemen yang spesifik agar produk tidak saling bercampur. Solusi yang diperoleh berupa rute pendistribusian sayuran organik yang meminimumkan total biaya distribusi, serta semakin bertambahnya lokasi maka semakin bertambah pula waktu komputasi yang diperlukan., The distribution problem of organic vegetables can be solved by the Multiple Trip Vehicle Routing Problem for Multiple Products and Compartments with Time Windows (MTVRPMPCTW) and solved by one exact method, namely Integer Linear Programming. The application of the model is carried out on three different cases, service for 5 locations with a single trip, service for 10 locations with multiple trip, and service for 15 locations with multiple trip and there are time windows that must be met. In the case of 10 locations and 15 locations, vehicles that have finished delivering organic vegetables must return to the depot and can carry out more than one distribution process if there are still locations that have not been served. Each location in all cases can order more than one type of organic vegetable. Products sent will be placed in a specific compartment so that the products do not mix with each other. The solution obtained is in the form of an organic vegetable distribution route that minimizes the total distribution cost, and the more locations, the more computational time required.
Keyword: distribution route, exact method, MTVRPMPCTW, organic vegetables

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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