A Study on Bi-metal 3D printing Technology Development based on Laser Technology

Kim, Chiyen The Korean Society of Industry Convergence 2020 한국산업융합학회 논문집 Vol.23 No.2

Additive manufacturing(AM) can create complex shapes directly in 3D CAD models with internal geometry compared to conventional subtraction manufacturing. AM technology has the advantage of adopting various materials as well as the reduction of material. However, the high cost of AM is still a significant barrier preventing the wider adoption of AM in industries. This paper analyzes the technical application cases for solving these entry barriers and proposes a bi-metal 3D printing technology as an anticipated application to overcome the difficulty. The paper investigates the complications for current 3D metal printing technology to conduct bi-metal 3D printing and addresses ongoing solution research based on laser technology.

A Study on the Physicochemical Properties Alteration of Aloe Saponaria Fermentation

Kweon, Do-Yeong,Kang, Min-Woo,Park, Jong-Min,Kim, Jong-Soon,Kwon, Soon-Goo,Choi, Won-Sik The Korean Society of Industry Convergence 2020 한국산업융합학회 논문집 Vol.23 No.6

This research focuses on the physicochemical characteristic of fermentation of Aloe Saponaria. The fermentation process applied in this study had 2 variation, depends on the aloe part as the materials (bottom, middle, and tip) and the initial sugar content (24% and 0%) used. Tests are conducted using uinkin fermented powder, sugar, salt, and distilled water as fermenting agent. The results indicate that change in physicochemical properties of aloe's skin was larger than in aloe's gel as fermentation materials. In contrast, there was no significant change in aloe's leaf during the process. A lso, aloes with intial sugar condition of 24% show better results than which without sugar addition in fermentation.

Characteristic of Lettuce (Lactuca sativa L.) Grown with Effective Microorganism and Bio-fertilizer

Kim, H.S.,Choi, S.M.,Supeno, D.,A., Okka,Chung, S.W.,Kim, H.S.,Kim, J.S.,Park, J.M.,Kwon, S.H.,Kwon, S.K.,Choi, Won Sik The Korean Society of Industry Convergence 2014 한국산업융합학회 논문집 Vol.17 No.3

The purpose of this study was to evaluate the growth of lettuce last for 36 days. Lettuce planted on the same medium with different treatment. The first treatment watering using bio-fertilizer (farmer) and second watering using effective microorganism. Lettuce grown in greenhouse with temperature $18-32^{\circ}C$.Characteristic observed that growth in height and weight of the plants. From the observations that can be generated at high observation, treatment 1 had a higher than treatment 2. On the last day treatment plant with treatment 1 had a 99.8 mm high while treatment 2 has height of 90.7 mm. Observation on severe treatment 1 has a heavier weight than treatment 2. Plants with treatment 1 have a weight on the last day of 0.15665 grams while in plants with treatment 2 weights are 0.11365 grams.

Structural Stability of High-temperature Butterfly Valve Using Interaction Analysis

Lee, Moon-Hee,Son, In-Soo The Korean Society of Industry Convergence 2020 한국산업융합학회 논문집 Vol.23 No.6

A butterfly valve is a valve that adjusts flow rate by rotating a disc for about 90° with respect to the axis that is perpendicular to the flow path from the center of its body. This valve can be manufactured for low-temperature, high-temperature and high-pressure conditions because there are few restrictions on the used materials. However, the development of valves that can be used in a 600℃ environment is subject to many constraints. In this study, the butterfly valve's stability was evaluated by a fluid-structured interaction analysis, thermal-structure interaction analysis, and seismic analysis for the development of valves that can be used in high-temperature environments. When the reverse-pressure was applied to the valve in the structural analysis, the stress was low in the body and seat compared to the normal pressure. Compared with the allowable strength of the material for the parts of the valve system, the minimum safety factor was approximately 1.4, so the valve was stable. As a result of applying the design pressures of 0.5 MPa and 600℃ under the load conditions in the thermal-structural analysis, the safety factor in the valve body was about 3.4 when the normal pressure was applied and about 2.7 when the reverse pressure was applied. The stability of the fluid-structure interaction analysis was determined to be stable compared to the 600℃ yield strength of the material, and about 2.2 for the 40° open-angle disc for the valve body. In seismic analysis, the maximum value of the valve's stress value was about 9% to 11% when the seismic load was applied compared to the general structural analysis. Based on the results of this study, the structural stability and design feasibility of high-temperature valves that can be used in cogeneration plants and other power plants are presented.

Investigation on Al-Si Coating Layer of Hot Stamped High-Strength Steel Plate

Kim, Dong-Gyu,Woo, Jong-Hoi,Son, Young-Min,Nam, Ki-Woo The Korean Society of Industry Convergence 2021 한국산업융합학회 논문집 Vol.24 No.2

In this study, Al-Si coating layer of hot stamped high-strength steel plate investigated. The coating layer in hot stamped high-strength steel plate was composed of a diffusion layer and a compound layer. As the hot stamping temperature and holding time for forming increased, the thickness of the coating layer in the Al-Si coated high-strength steel plate increased. The thickness of coating layer after hot stamping with holding time of 500 sec at 890, 910 and 950℃ was obtained 8.9, 11.8, and 20.6 ㎛, respectively. The thickness of coating layer after hot stamping with holding time of 180, 500 and 850 sec at 910℃ was obtained 5.7, 11.8, and 17.8 ㎛, respectively. The compound layer consists of Al_5.4Fe₂ and Fe₂Si phases.

Human Activity Recognition with LSTM Using the Egocentric Coordinate System Key Points

Wesonga, Sheilla,Park, Jang-Sik The Korean Society of Industry Convergence 2021 한국산업융합학회 논문집 Vol.24 No.6

As technology advances, there is increasing need for research in different fields where this technology is applied. On of the most researched topic in computer vision is Human activity recognition (HAR), which has widely been implemented in various fields which include healthcare, video surveillance and education. We therefore present in this paper a human activity recognition system based on scale and rotation while employing the Kinect depth sensors to obtain the human skeleton joints. In contrast to previous approaches that use joint angles, in this paper we propose that each limb has an angle with the X, Y, Z axes which we employ as feature vectors. The use of the joint angles makes our system scale invariant. We further calculate the body relative direction in the egocentric coordinates in order to provide the rotation invariance. For the system parameters, we employ 8 limbs with their corresponding angles each having the X, Y, Z axes from the coordinate system as feature vectors. The extracted features are finally trained and tested with the Long short term memory (LSTM) Network which gives us an average accuracy of 98.3%.

Floating Gas Power Plants

Kim, Hyun-Soo The Korean Society of Industry Convergence 2020 한국산업융합학회 논문집 Vol.23 No.6

Specification selection, Layout, specifications and combinations of Power Drives, and Ship motions were studied for FGPP(Floating Gas-fired Power Plants), which are still needed in areas such as the Caribbean, Latin America, and Southeast Asia where electricity is not sufficiently supplied. From this study, the optimal equipment layout in ships was derived. In addition, the difference between engine and turbine was verified through LCOE(Levelized Cost of Energy) comparison according to the type and combination of Power Drives. Analysis of Hs(Significant Height of wave) and Tp(spectrum Peak Period of wave) for places where this FGPP will be tested or applied enables design according to wave characteristics in Brazil and Indonesia. Normalized Sloshing Pressures of FGPP and LNG Carrier are verified using a sloshing analysis program, which is CFD(Computational Fluid Dynamics) software developed by ABS(American Bureau of Shipping). Power Transmission System is studied with Double bus with one Circuit Breaker Topology. A nd the CFD analysis allowed us to calculate linear roll damping coefficients for more accurate full load conditions and ballast conditions. Through RAO(Response Amplitude Operator) analysis, we secured data that could minimize the movement of ships according to the direction of waves and ship placement by identifying the characteristics of large movements in the beam sea conditions. The FGPP has been granted an AIP(Approval in Principle) from a classification society, the ABS.

Studies on the Width of Rectangular Channels of Fuel Cell Bipolar Plate Using FDM 3D Printer with PLA Filament

Kim, Jae-Hyun,Jin, Chul-Kyu The Korean Society of Industry Convergence 2021 한국산업융합학회 논문집 Vol.24 No.6

Bipolar plates with channel width of 0.5 mm, 0.4 mm, and 0.3 mm respectively were printed using a 3D printer. The shape of three b ipolar plates was rectangular, the channel depth was 0.5 mm, and the thickness of base was 0.5 mm. The bipolar plate with channel width of 0.5 mm had 45 channels, and their active area was 44.5 mm × 50 mm. The bipolar plate with channel width of 0.4 mm had 57 channels and its active area was 45.2 mm × 50 mm, and the bipolar plate with channel width of 0.3 mm had 75 channels and its active area was 44.7 mm × 50 mm. The bipolar plates were printed using PLA filament. The cross-sectional lengths of the bipolar plates with channel widths of 0.5 mm and 0.4 mm were identical by 96% of the designed cross-sectional length. Whereas the bipolar plate with a channel length of 0.3 mm had a large difference of 25% from the designed cross-sectional length.

Tribological Properties and Friction Coefficient Prediction Model of 200μm Surfaces Micro-Textured on AISI 4140 in Soybean Crusher

최원식,프라타마 판두 산디,수페노 데스티아니,변재영,이은숙,우지희,양지웅,키프 디마스 하리스 신,크리스타 마이난다 브리기타,오케추쿠 나에메카 니콜라스,이강삼,Choi, Wonsik,Pratama, Pandu Sandi,Supeno, Destiani,Byun, Jaeyoung,Lee, Ensuk,Woo, Jihee,Yang, Jiung,Keefe, Dimas The Korean Society of Industry Convergence 2018 한국산업융합학회 논문집 Vol.21 No.5

In this research, the effect of normal load, sliding velocity, and texture density on thefriction coefficient of surfaces micro-textured on AISI 4140 under paraffin oil lubrication were investigated. The predicted tribological behavior by numerical calculation can be serves as guidance for the designer during the machine development stage. Therefore, in this research friction coefficient prediction model based on response surface methodology (RSM), support vector machine (SVM), and artificial neural network (ANN) were developed. The experimental result shows that the variation of load, speed and texture density were influence the friction coefficient. The RSM, ANN and SVM model was successfully developed based on the experimental data. The ANN model can effectively predict the tribological characteristics of micro-textured AISI 4140 in paraffin oil lubrication condition compare to RSM and SVM.

Autonomous Tracking of Micro-Sized Flying Insects Using UAV: A Preliminary Results

Ju, Chanyoung,Son, Hyoung Il The Korean Society of Industry Convergence 2020 한국산업융합학회 논문집 Vol.23 No.2

Tracking micro-sized insects is one of the challenges of protecting ecosystems and biodiversity. In this study, we propose an approach for the autonomous tracking of micro-sized flying insects, and develop an unmanned aerial vehicle (UAV)-based robotic system. The Kalman filter is applied to the received signal strength emitted from radio telemetry to estimate the position while reducing the measurement error and noise. The autonomous tracking strategy is a method in which the UAV rotates at one point to measure the signal strength and control its position in the strongest direction of the signal. We also design a system architecture comprising a tracking sensor system and a UAV system for micro-sized insects. The estimation and autonomous tracking of the target position by the proposed system are verified and evaluated through dynamic simulation. Therefore, in this study, we propose and validate a UAV-based tracking system for micro-sized flying insects, which has not been proposed in studies conducted thus far.