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Jung Sik Jeong, Jaeyong Jeong, Hye-Jin Kim and Sun-Young Kim

ABSTRACT

This research aims at investigating the user requirements at the service level for safe navigation system, following e-navigation strategy implementation plan. The user requirements is surveyed to collect real-time navigational information and then to find out services through the presentation of the collected information. To provide the information on user needs for the system developer, a questionnaire survey has been made. Based on this surveys, this research investigated which navigational information is with higher priority for the safe navigation during ship operation by bridge team in harbour and in coastal and confined.

Open access

Jae-Yeon Kim, Jung-Woo Hwang, Hye-Young Kim, Seung-Mi Lee, Woo-Sang Jung and Jai-Won Byeon

Abstract

Double-pass Friction Stir Processing (FSP) was applied to fabricate an AZ31/CNT nano-composite for surface hardening of lightweight structural components. The effects of double-pass FSP as well as groove depth (i.e., volume fraction of CNT) on the CNT distribution, dynamically recrystallized grain size, and resulting microhardness were studied. Double-pass FSP was performed for the CNT-filled plate-type specimen with different groove depths of 2, 3, and 4 mm. By applying double-pass FSP, the average size of CNT clusters decreased, implying a more homogeneous distribution. Compared with the FSPed specimen without CNT, grain size was refined from 19 μm to 3 μm and microhardness increased from 52 Hv to 83 Hv (i.e., 71% increase).