Korea Institute of Machinery & Materials

Air purifier performance in an occupied office: Field CADR and effectiveness from a reconstructed device-off condition

Air-purifier performance in an occupied building is hard to assess because the indoor concentration without the device cannot be observed under the same conditions. This study reconstructs that device-off condition from long-term field measurements in an occupied office. Two sequ...

Multisensor Characterization of Process Behavior During Underwater Laser Cutting of 100 mm Thick STS 304 Stainless Steel

Underwater laser cutting is a promising remote segmentation method for highly activated reactor internals because it enables non-contact cutting while maintaining water shielding. Although previous studies have demonstrated the feasibility of thick-section underwater laser cuttin...

Development of a Two-Dimensional Bead Shape Prediction Algorithm for Fillet FCAW Considering Welding Speed and Torch Offset

Automated welding processes have become increasingly critical in the shipbuilding, automotive, and aerospace industries. Precise weld seam tracking is essential for reliable automated welding, as torch misalignment causes weld defects and significant variations in bead geometry....

Uncertainty quantification and parameter optimization of a plasma etching process using a heteroscedastic Gaussian process

This study presents an uncertainty-aware framework for the reliability-based robust design optimization (RBRDO) of plasma etching processes in semiconductor manufacturing. The framework is demonstrated using experimental measurements of the remaining thickness collected at nine w...

Temporal max pooling for robust multi-class fault diagnosis of PMSM-based drive modules at unseen sensor locations

Abstract In vibration-based fault diagnosis of permanent magnet synchronous motor (PMSM) drive modules, sensor relocation can induce distribution shifts that degrade classification performance and increase diagnostic errors. This study evaluates whether a lightweight diagnostic m...

Design and experimental evaluation of a multi-winding gas-spring gravity compensation mechanism for high-torque sit-to-stand assistance

Conventional gravity compensators capable of handling large loads are often bulky and require hardware modifications for different payload ranges. This study presents a multi-winding gas-spring gravity compensation mechanism (MW-GCM) for high-torque sit-to-stand assistance and ev...

Influence of base metal geometry on heat dissipation, molten pool dynamics, and solidification behavior in GMAW bead formation

The geometrical configuration of the base metal can alter heat dissipation and molten pool behavior during gas metal arc welding (GMAW), even when the same nominal welding parameters are applied. This study investigated the effect of base metal width on heat dissipation, bead mor...

Effect of intake air temperature on combustion characteristics and operation range of high-pressure ammonia direct injection engine

Ammonia is emerging as a promising carbon-free fuel, particularly for internal combustion engines, due to its high hydrogen content and potential for sustainable production. However, ammonia's low flame speed and narrow flammability limit pose challenges to combustion stability a...

Optimal waste heat temperature in semiconductor cleanroom HVAC: Configuration-dependent cost structure and operating strategy

Heating, ventilation, and air-conditioning (HVAC) systems account for a large share of the energy use of advanced semiconductor fabrication facilities (fabs). Recovering chiller condenser waste heat to outdoor air conditioner (OAC) heating coils in place of LNG boiler heating has...