A study on the fracture characteristics of tapered double cantilever beams made of heterogeneous composites with adhesive interfaces

Journal of Mechanical Science and Technology - In this study, CFRP and aluminum properties were investigated by carrying the static experiment on the shape-dependent bonding structure, and designed...     

Design,Implementation, and Validation of KOMPSAT‐2 Software Simulator

In this paper, we present design features, implementation, and validation of a satellite simulator subsystem for the Korea Multi‐Purpose Satellite‐2 (KOMPSAT‐2). The satellite simulator subsystem is implemented on a personal computer to minimize costs and trouble on embedding onboard flight software into the simulator. An object‐oriented design methodology is employed to maximize software reusability. Also, instead of a high‐cost commercial database, XML is used for the manipulation of spacecraft characteristics data, telecommand, telemetry, and simulation data. The KOMPSAT‐2 satellite simulator subsystem is validated by various simulations for autonomous onboard launch and early orbit phase operations, anomaly operation, and science fine mode operation. It is also officially verified by successfully passing various tests such as the satellite simulator subsystem test, mission control element system integration test, interface test, site installation test, and acceptance test.     

Characteristic evaluation of friction and wear in the C-N and TiN coated gear

C-N films were deposited on the 20CrMo alloy steel substrate by the Plasma Source Ion Implantation (PSII) method and TiN films were coated on the same material by the Physical Vapor Deposition (PVD) method. It was found that friction coefficient of C-N coating were relatively lower than TiN coating. And with the load increased, the friction coefficients of C-N coating and TiN coating were both decreased. Then the author puts forward the test rig, working under the conditions of 1,800 rpm, 20 N·m for 100 h. The observations by microscope showed the wear reduced. The antiwearing performance enhanced prominently. But the TiN coated gear had a more serious friction phenomenon than C-N coated gear. This is caused by that coating of TiN, which was made at a high temperature about 500°C. The high temperature led to the substrate intenerated and the surface hardness had decreased from 850 HV to 630 HV. PSII method eliminates the tempering problem of the coating of C-N films, which had better wear resistance than TiN films. The friction and wear resistance of gears which coated by C-N films ameliorated significantly.     

The credit analysis of recycling beryllium and uranium in BeO-UO2 nuclear fuel

This study quantifies the credits of beryllium and uranium which are used as the raw materials for BeO-UO₂ nuclear fuel by analyzing the influence of their credits on the nuclear fuel cycle cost was analyzed, where the credit was defined as the value of raw materials recovered from spent fuel and the raw materials that were re-cycled. The credits of beryllium and uranium at 60 MWD/kg burn-up were –0.22 Mills/kWh and –0.14 Mills/kWh, respectively. These findings were based on the assumption that the optimal mixing proportion of beryllium in the BeO-UO₂ nuclear fuel is 4.8 wt%. In sum, the present study verified that the credits of beryllium and uranium in relation to BeO-UO₂ nuclear fuel are significant cost drivers in the cost of the nuclear fuel cycle and in estimating the nuclear fuel cycle of the reprocessing option for spent nuclear fuels.