Judul: Multi-Depot Electric Vehicle Routing Problem with Time  Windows
Abstrak: Dunia sedang menghadapi masalah perubahan iklim yang salah satu penyebabnya adalah emisi gas rumah kaca. Emisi gas rumah kaca dapat dikurangi dengan menggunakan kendaraan listrik. Kendaraan listrik memiliki jarak tempuh yang terbatas. Oleh karena itu, perlu dilakukan penentuan rute optimal, salah satunya adalah penentuan rute kendaraan listrik multi-depot dengan time windows. Tujuan dari penelitian ini adalah memodelkan masalah penentuan rute kendaraan listrik multi-depot dengan time windows dalam model MDEVRPTW dan menyelesaikannya dengan mixed integer linear programming. Biaya yang diminimumkan meliputi biaya tetap kendaraan, biaya perjalanan, biaya pengisian daya, dan biaya penalti jika melanggar time windows. Kendaraan diperbolehkan melanggar time windows dengan toleransi waktu 5 menit dari time windows setiap lokasi. Model ini diimplementasikan dalam dua kasus yang dibagi menjadi lima skenario per kasus. Setiap skenario memiliki perbedaan dalam kapasitas baterai, kapasitas muatan, dan time windows pelanggan. Pada kasus pertama, kendaraan harus kembali ke depot asalnya, sedangkan pada kasus kedua, kendaraan bisa kembali ke depot terdekat. Solusi yang dihasilkan berupa rute kendaraan listrik yang meminimumkan total biaya untuk setiap skenario dan kasus, dan memenuhi semua kendala yang ditetapkan., The world is currently facing the issue of climate change, one of the causes is greenhouse gas emissions. Greenhouse gas emissions can be reduced by using electric vehicles. However, electric vehicles have a limited range. Therefore, it is necessary to determine the optimal route, one of which is the multi-depot electric vehicle routing problem with time windows. The aim of this research is to model the multi-depot electric vehicle routing problem with time windows in the MDEVRPTW model and solve it using mixed integer linear programming. The costs minimized in this problem include vehicle fixed costs, travel costs, charging costs, and penalty costs for violating time windows. Vehicles are allowed to violate time windows with a tolerance of 5 minutes. This model is implemented in two cases, each divided into five scenarios. Each scenario differs in vehicle battery capacity, vehicle load capacity, and customer time windows. In the first case, vehicles must return to their original depot, while in the second case, vehicles can return to the nearest depot. The result is the electric vehicle route that minimizes total costs for each scenario and case, and meets all the specified constraints.
Keyword: time windows, electric vehicle, MDEVRPTW, depot

Judul: Masalah Perutean Kendaraan Listrik Multi-Perjalanan dengan Keberadaan Stasiun Penukaran Baterai
Abstrak: Dengan meningkatnya kesadaran terhadap emisi gas rumah kaca, masyarakat lebih cenderung menggunakan kendaraan listrik dalam berbagai layanan distribusi. Masalah rute pendistribusian dapat diselesaikan dengan menggunakan Electric Vehicle Routing Problem (EVRP). EVRP merupakan perluasan dari VRP klasik dengan kendala keterbatasan kapasitas baterai sehingga kendaraan listrik diharuskan mengunjungi stasiun penukaran baterai dalam perjalanan. Pada makalah ini akan dijelaskan tentang Multiple Trips Electric Vehicle Routing Problem (MTEVRP) dengan keberadaan Stasiun Penukaran Baterai Kendaraan Listrik Umum (SPBKLU). Kendaraan listrik dapat melakukan lebih dari satu kali perjalanan dalam memenuhi permintaan tiap lokasi. Fungsi objektifnya bertujuan meminimumkan konsumsi energi baterai pada kendaraan listrik serta meminimumkan jarak tempuh, di mana kedua hal tersebut berbanding lurus dengan biaya pengiriman maka dengan meminimumkan kedua hal tersebut secara otomatis dapat meminimumkan biaya pengiriman. Permasalahan ini akan diselesaikan dengan metode eksak yaitu Integer Linear Programming., In connection with the increasing awareness of greenhouse gas emissions, people are more inclined to use electric vehicles in various distribution services. The distribution route problem can be solved using the Electric Vehicle Routing Problem (EVRP). EVRP is an extension of the classic VRP with the constraint of limited battery capacity so that electric vehicles are required to visit recharging stations on the way. In this study, we will explain the Multiple Trips Electric Vehicle Routing Problem with Battery Swapping Stations. The electric vehicle can make more than one trip to fulfill the demand of each location. The objective function is minimizing the electric vehicle's battery energy consumption and the travel distance, both of which are directly proportional to the shipping cost, so minimizing these two things can automatically minimize the shipping cost. This problem will be solved with an exact method: Integer Linear Programming.
Keyword: battery swapping stations, electric VRP, exact method, multiple trips, MTEVRP

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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