Judul: Electric Vehicle Routing Problem with Soft Time Windows
Abstrak: Masalah perutean kendaraan listrik merupakan perkembangan dari masalah perutean kendaraan konvensional dengan karakteristik unik yang tidak dimiliki kendaraan konvensional. Masalah perutean kendaraan listrik dengan soft time windows memiliki beberapa fitur yang membuat model menjadi lebih fleksibel untuk diimplementasikan. Fitur tersebut antara lainnya adalah tersedianya stasiun pengisian daya kendaraan listrik umum (SPKLU) yang dapat dikunjungi kendaraan sebanyak yang diperlukan serta jumlahnya dapat disesuaikan. Model juga dapat menyesuaikan jumlah dan tipe kendaraan yang digunakan dalam sekali perutean. Tipe kendaraan listrik dapat berupa kendaraan homogen dengan kapasitas muatan dan baterai seragam ataupun heterogen dengan perbedaan kapasitas muatan dan baterai. Terdapat aturan soft time windows yang memberikan fleksibilitas waktu, memungkinkan kendaraan untuk melanggar aturan waktu dengan pemberian biaya penalti. Dalam mengimplementasikan model, tujuh kasus diuji dengan variasi jumlah kendaraan, kapasitas muatan dan baterai kendaraan, jumlah pelanggan dan SPKLU, dan aturan time windows. Penyelesaian masalah ini menggunakan metode eksak menghasilkan solusi optimum yang menciptakan rute perjalanan dengan biaya minimum sesuai dengan aturan soft time windows dan kendala lainnya., The electric vehicle routing problem is a development of vehicle routing problems with unique characteristics not found in conventional vehicles. The electric vehicle routing problem with soft time windows has several features that make the model flexible for implementation. These features include the availability and quantity of charging stations that vehicles can visit as needed can be adjusted. The model can also adapt the number and type of vehicles used in a single routing. Types of electric transport used in this model can be homogeneous with uniform cargo and battery capacity or heterogeneous with different load and battery capacity. There are soft time window rules that provide time flexibility, allowing vehicles to violate time rules with penalty costs. In implementing the model, we used seven cases with variations of number of vehicles, vehicle cargo capacity, vehicle battery capacity, the number of customers and charging stations, and time window rules. Solving this problem using an exact method results in an optimal solution that creates a travel route with minimum costs according to soft time window rules and other constraints.
Keyword: electric vehicle, SPKLU, time windows

Judul: Pengoptimuman Proses Antar Jemput Barang Menggunakan Kendaraan Listrik
Abstrak: Sebuah perusahaan logistik perlu menentukan rute yang optimal untuk meminimalkan biaya operasional dalam pendistribusian produk. Permasalahan pendistribusian ini, khususnya antar jemput barang secara simultan dapat diselesaikan dengan Vehicle Routing Problem with Simultaneous Pickup and Delivery (VRPSPD). Peralihan kendaraan konvensional ke kendaraan listrik merupakan salah satu upaya perusahaan dalam mengurangi gas emisi rumah kaca. Pada penelitian ini akan menyelesaikan permasalahan proses antar jemput barang menggunakan kendaraan listrik yang dimodelkan dengan Electric Vehicle Routing Problem with Simultaneous Pickup and Delivery (EVRPSPD). Kendaraan listrik yang digunakan pada model ini memiliki keterbatasan daya sehingga perlu mengisi daya pada Battery Swapping Station (BSS). Selanjutnya, model akan diimplementasikan pada berbagai macam kasus berbeda yang diselesaikan menggunakan metode eksak dengan bantuan software Lingo 18.0. Hasil yang diperoleh berupa rute distribusi yang optimal dengan meminimumkan jarak serta kendaraan listrik yang mengunjungi BSS untuk pengisian ulang daya., A logistic company needs to determine the optimal route to minimize operational costs in product distribution. This distribution problem, especially the simultaneous pickup and delivery of goods can be solved using the Vehicle Routing Problem with Simultaneous Pickup and Delivery (VRPSPD). The transition from conventional vehicles to electric vehicles is one of efforts carried-out by company in reducing greenhouse gas emission. This research aims to solve the pickup and delivery process problem using electric vehicles, modeled as the Electric Vehicle Routing Problem with Simultaneous Pickup and Delivery (EVRPSPD). The electric vehicles used in this model have limited power and need to recharge at a Battery Swapping Station (BSS). Furthermore, the model will be implemented in various different cases using an exact method with the assistance of Lingo 18.0 software. The results obtained include an optimal distribution route by minimizing the distance traveled and the electric vehicles visiting the BSS for recharging.
Keyword: battery swapping, VRPSPD, electric vehicle, route optimization

Judul: Hydroxyapatite-Chitosan Composite Coating on Stainless Steel 316 to Improve Corrosion Resistance
Abstrak: Metals that were used in bone implantation should have good corrosion resistance that were not easily corroded when implanted into the body. Metal corrosion resistance of stainless steel 316 can be enhanced through the metal coating by hydroxyapatite-chitosan composite with composition ratio of hydroxyapatite (gram) and chitosan 3% (mL) 0.2:0, 0.2:0.1, 0.2:0.5, 0.2:1.0, and 0.2:1.5. Besides improving the corrosion resistance of metal, the presence of chitosan also maintain the position of hydroxyapatite on metal surfaces. Corrosion resistance increases with increasing amount of chitosan added and the best composition of hydroxyapatite-chitosan composite was 0.2:1.0.
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